. . *
o • »
-o *^T* <v
»* v \
- ° " "
** v \
1 v*<<; %
,0 O * ( 7T. A. ^
o . »
/x '•«• .♦♦*% « y
■^- > %^
ijk ; /^ «i?> o ^°^ ^iiiK ; ^°** yassv *°-v vssep; *«°* -life'
^tiatey* /,•£;%% ^*££k°» / •"
>d» :«f&- *bi* --calk- *w «P^ <>u<v
W .-isfifel-. V>*
X.-^ii-% £*X&k°» ^<^/^ /*-
C U ♦'
P v >
♦ y -v.
Bureau of Mines Information Circular/1981
Regulations and Substitutes
A Compliance Manual
for the U.S. Mining Industry
By R. A. Westin, R. P. Barruss, B. Woodcock,
and R. L. King
UNITED STATES DEPARTMENT OF THE INTERIOR
Information Circular 8838
Regulations and Substitutes
A Compliance Manual
for the U.S. Mining Industry
By R. A. Westin, R. P. Barruss, B. Woodcock,
and R. L. King
UNITED STATES DEPARTMENT OF THE INTERIOR
James G. Watt, Secretary
BUREAU OF MINES
This publication has been cataloged as follows
Polychlorinated biphenyls: Regulations and substitutes.
(Information circular - Bureau of Mines ; 8838)
Includes bibliographical references.
Supt. Docs no.: I 28.27:8838.
1. Polychlorinated biphenyls— Handbooks, manuals, etc. 2. Elec-
tricity in mining— Handbooks, manuals, etc. I. Westin, Robert A. II.
Series: United States. Bureau of Mines. Information circular ; 8838.
TN295.U4 [T55.3.H3] 622s [363. 1'79] 80-607190
PCB's used in the U.S. mining industry 4
General requirements 6
Recordkeeping (40 CFR 761.45) 6
Marking (40 CFR 761.20) 7
Containers for PCB's (40 CFR 761.42) 8
Storage (40 CFR 761.42) 9
Spill cleanup [40 CFR 761.10(d)] 9
Other information 10
Other regulations 10
Decontamination (40 CFR 761.43) 11
Transportation [40 CFR 761.42, 761.20(b)] 11
Disposal (40 CFR 761.10) 12
Askarel transformers 12
Uses of askarel transformers in mining 13
Machine mounted 13
Number of askarel transformers used in U.S. mines 15
How to identify an askarel-filled transformer 17
EPA requirements for PCB (askarel) transformers 18
Precautions for continued use. 20
Significance of water 20
Decision guide 21
Fences and vehicle barriers 28
Curbs and doorway dikes 29
Emergency foam packs 29
Special problems 29
Mobile mining machinery 30
Relocation of transformers 31
Retrof illing 31
Non-PCB replacement transformers 32
Characteristics of non-PCB replacement transformers 33
Oil-filled transformers 33
Silicone transformer liquid 34
High-fire-point transformer liquids 34
Open air-cooled transformers 35
Sealed gas-filled transformers 36
Cast coil transformers.... 37
Mining machinery transformers 37
Relative costs of non-PCB replacement transformers 38
Summary — considerations in choosing an alternative to PCB
PCB-contaminated transformers ♦ 40
PCB capacitors 42
Uses of PCB capacitors in the mining industry 42
How ~tp identify PCB capacitors 42
Requirements for PCB capacitors 43
Precautions for continued use 45
Substitutes for PCB capacitors 45
Underground mining machinery 46
EPA requirements 47
Recommended precautions for continued use 48
Emergency spill response 49
Non-PCB replacement equipment 49
EPA requirements 50
Recommended precautions for continued use 51
Emergency spill response 52
Non-PCB electromagnets 52
Heat-transfer fluids 53
EPA requirements 53
Recommended precautions for continued use 55
Emergency spill response 55
Non-PCB heat-transfer fluids 56
Hydraulic fluids 56
EPA requirements 56
Non-PCB hydraulic fluids 57
Waste oil 57
EPA requirements 57
Appendix A. — Outline of PCB spill response guide 58
Appendix B. — Water-only drainage system 59
1. Toxic Substances Control Act 5
2. Typical transformer and switch gear on concrete mounting pad with
steel dike installed 24
3. Shop preparation of 6- by 3.5-inch angle-steel dike edge, including
mitre-cut and ground ends and holes to be drilled 25
4. Corner joints — 2- by 2-inch steel angle 25
5. View of corner joint, top view detail of corner joint, and section
through dike 26
6. Side view and pictorial view from top of the water-only drainage
7. Schematic diagram of basic parts and dimensions of an extended
mounting pad 27
8. Vehicle barrier suitable for protection of an askarel transformer
located in a parking lot or next to a street 28
B-l. Copper plumbing pipe with cap and fitting 59
B-2. Valve face 59
B-3. Bottom view of valve face 60
B-4. Two pieces brazed on valve face 60
B-5. Rectangular piece of copper for "guard plate" 60
B-6. Brazing of "guard plate" to main body of valve 61
B-7. "Valve rest" 61
B-8. Bearing support holes and hole-locating jig 62
B-9. Silicone rubber for "flapper valve" 63
B-10. "Flapper valve" as made by method (a) 63
B-ll. Mold half for pattern of "flapper valve" 64
B-12. Hinge support for flapper valve 64
B-13. Pipe flange 65
B-14. Fitting of drain valve and flange into inside of dike 65
B-15. Screen covering valve system..... 66
1. Manufacturers and trade names of PCB's 3
2. Summary of askarel transformer data gathered during visits to
3. Extrapolated estimates of numbers of askarel transformers in
various mining segments 17
4. Cost comparisons of oil-filled versus other transformer designs
intended for hazardous locations 39
5. Quantity of PCB's in mining machinery 46
POLYCHLORINATED BIPHENYLS: REGULATIONS AND SUBSTITUTES
A Compliance Manual for the U.S. Mining Industry
R. A. Westin, 1 R. P. Barruss, 2 B. Woodcock, 3 and R. L. King*
Polychlorinated biphenyls (PCB's) have been widely utilized as fire-
resistant dielectric coolants in electrical equipment used in mining
applications, including transformers, capacitors, electric motors, and elec-
tromagnets. In addition, PCB's have been used in hydraulic fluids and heat-
transfer fluids and are present in many oil-filled transformers. The
U.S. Environmental Protection Agency (EPA) recently banned the manufacture of
PCB's and equipment using PCB's, and imposed strict requirements on the con-
tinued use and disposal of existing PCB equipment. This manual discusses the
EPA requirements, suggests ways to decrease the risks resulting from continued
use of PCB equipment, and surveys the non-PCB equipment that is available as
replacements for the PCB electrical equipment presently used in mines.
The U.S. Environmental Protection Agency (EPA) recently banned the manu-
facture of new equipment containing polychlorinated biphenyls (PCB's) and
established stringent requirements on the continued use and disposal of exist-
ing equipment containing PCB's. These regulations apply to all PCB's in the
United States, Puerto Rico, Virgin Islands, and U.S. Pacific territories. All
PCB's are regulated, including those in use in equipment in surface and under-
PCB's have been the basis for fire-resistant askarel liquids used in
transformers and capacitors and have been used in various other applications
in the mining industry. A contract (J01 77046) was awarded by the U.S. Depart-
ment of Interior, Bureau of Mines, to Versar, Inc., Springfield, Va., to study
(1) how to comply with EPA regulations and (2) how to select replacements for
equipment that contains PCB's. The information in this manual addresses these
1 Senior chemical engineer, Versar, Inc., Springfield, Va.
2 Senior mechanical engineer, Versar, Inc., Springfield, Va.
%echanical engineer, Versar, Inc., Springfield, Va.
^Technical project officer, Pittsburgh Research Center, Bureau of Mines,
A necessary supplement to this manual is a copy of the EPA regulations on
PCB's. Reprints of the PCB Ban Regulation (published in the May 31, 1979,
Federal Register) are available from EPA, along with a list of the EPA-
approved PCB Disposal Facilities. Additional background information on the
regulation is also available in the EPA Support Document to the PCB Ban Regu-
lation. Te, obtain copies of all of these reports, call (toll-free,
800-424-9065, or in Washington, D.C., local 554-1404) or write the Office of
Industry Assistance, Office of Toxic Substances TS-799, U.S. Environmental
Protection Agency, 401 M St., S.W., Washington, D.C. 20460.
Note for potash and phosphate mines and mills : On May 9, 1980, the EPA
proposed the following regulations: " except for small PCB capacitors and
except for facilities manufacturing anhydrous liquid ammonia, the use or stor-
age of PCB items, as defined in sec. 761.2 (x), at facilities manufacturing,
processing, or storing bulk, unpackaged fertilizer or agricultural pesticides
is prohibited" (Federal Register, page 30993). This regulation has not yet
been promulgated, nor is it known whether it will affect the use of PCB's in
potash and phosphate mines or mills. For advice as to whether this will
affect the continued use of PCB's at your installation, call (toll-free,
800-424-9065, or in Washington, D.C, local 554-1404) or write the Office of
Industry Assistance, Office of Toxic Substances TS-799, U.S. Environmental
Protection Agency, 401 M St., S.W., Washington, D.C. 20460.
Other available information : This report does not go into much detail
about the health and environmental effects of PCB's or the chemicals now being
used as substitutes for PCB's. The following reports cover these technical
areas; the NIOSH Criteria Document is particularly recommended for its discus-
sion of health issues if you are going to service PCB equipment or clean up
National Institute for Occupational Safety and Health. Criteria for a
Recommended Standard. . .Occupational Exposure to Polychlorinated Biphenyls
(PCB's). Pub. 77-225, September 1977; available from U.S. Government
Printing Office, Washington, D.C.
U.S. Environmental Protection Agency. Assessment of the Use of Selected
Replacement Fluids for PCB's in Electrical Equipment. Rept. EPA 560/6-
77-008, March 1979; available from National Technical Information Service,
Springfield, Va. , PB 296 377.
Interdepartmental Task Force in Polychlorinated Biphenyls. Polychlorinated
Biphenyls and the Environment. 1972; available from National Technical
Information Service, Springfield, Va. , Rept. NTIC COM-72-10419.
Versar, Inc. PCB's in the United States: Industrial Use and Environmental
Distribution. Feb. 25, 1976; available from National Technical Information
Service, Springfield, Va., PB 252 012.
Polychlorinated biphenyls (PCB's) are a class of chemicals that have been
used since 1930 as the basis for nonflammable dielectric liquids in electrical
equipment such as transformers and capacitors and as a component of some heat-
resistant, heat-transfer, and hydraulic fluids. PCB's were manufactured in
the United States from 1930 through 1977, primarily by Monsanto Industrial
Chemicals Co., 5 which marketed various mixtures of PCB's under the trade name
Aroclor. Mixtures of PCB's and other chemicals were marketed by Monsanto and
by other companies under a variety of trademarks for different applications as
described later in this report. PCB's have also been manufactured in Europe
and Japan, as listed in table 1.
TABLE 1. - Manufacturers and trade names of PCB's
Kanegaf uchi ,
Prodelec. . «
United Kingdom and United
United Kingdom and Japan. .
United Kingdom and Europe.
PCB's were identified as a serious and widespread environmental pollutant
in 1968, leading Monsanto to voluntarily limit the sales of PCB's to "totally
enclosed" capacitor and transformer applications after 1972. Limitations on
the presence of PCB's in food were established by the U.S. Food and Drug
Administration (FDA) in 1973. In 1977, the EPA banned the discharge of PCB's
into the water effluents from PCB manufacturers, capacitor manufacturers, and
transformer manufacturers. A review of the uses and environmental distribu-
tion of PCB's in 1975 indicated that more than half the 1.5 billion pounds of
PCB's that had ever been manufactured in the United States were still in use
in electrical equipment and that only about 10 percent of the total PCB's had
entered the environment. Even this relatively low environmental load of PCB's
was sufficient to cause the PCB concentration in some freshwater fish to
exceed the limits set by the FDA. The resulting ban on the sale of contami-
nated fish essentially ended commercial fishing on the Hudson River, in much
of the Great Lakes, and in a number of other freshwater lakes and rivers.
5 Use of brand names is for identification purposes only and does not imply
endorsement by the Bureau of Mines.
The environmental and health problems associated with exposure to PCB's
result from the same properties that make these chemicals useful in industrial
and electrical applications: PCB's are very stable chemically, are soluble in
organic solvents, and are almost insoluble in water. PCB's that are released
to the environment do not degrade, but accumulate preferentially in the fat of
micro-organisms and bioaccumulate in the food chain. As a result, the concen-
tration of PCB's in fish may be 1 million times higher than in the water that
the fish lives in. Many organic compounds that are insoluble in water are
excreted by birds and mammals by being converted to water-soluble compounds by
powerful enzymes in the liver. High concentrations of water-insoluble chemi-
cals in the body will cause the liver to increase the production of these
enzymes. Unfortunately, PCB's are immune to attack by these enzymes and so
are not excreted but instead build up in the body, causing the liver to con-
tinue its increased production of the enzymes. Although the enzymes do not
react with the PCB's, they will react with various hormones, and the increase
in enzyme levels in the body activated by PCB concentration results in
decreased levels of these hormones, which causes decreased shell thickness in
bird eggs and reproductive problems in mammals. PCB's do not appear to be a
direct cause of cancer, but the enzyme changes caused by exposure to PCB's may
make the body more susceptible to the effects of low levels of direct carcin-
ogens found in cigaret smoke and in other manmade environmental pollutants.
Ingestion of relatively large quantities of PCB's (on the order of 1 gram) can
cause liver damage, skin problems, and other acute health effects.
In 1976, the U.S. Congress passed the Toxic Substances Control Act, which
gave the EPA wide authority to control the production and use of chemicals in
the United States. Section 6(e) of this act mandated a complete ban on the
manufacture, processing, distribution in commerce, and use of PCB's and
required the EPA to establish requirements for the marking and disposal of
PCB's in use (fig. 1). The act also allowed the EPA to authorize the contin-
ued use of PCB's after July 1, 1979, if the agency found that such use did not
present undue risk to human health or the environment. The EPA promulgated
the required Disposal and Marking Regulations for PCB's on February 17, 1978,
and on May 31, 1979, promulgated the PCB Ban Regulations, which authorize cer-
tain continued uses of PCB's and specify the conditions that must be met by
those who continue to use PCB's.
PCB's Used in the U.S. Mining Industry
The EPA regulations on the marking, processing, use, and disposal of
PCB's will affect the following equipment and activities in the mining
1. Askarel transformers: Marking, maintenance, disposal, spill
cleanup, recordkeeping, storage for disposal.
2. Oil-filled transformers: Disposal of oil.
3. Capacitors: Marking, disposal, spill cleanup, recordkeeping,
storage for disposal.
Section 6(e), Toxic Substances Control Act
PUBLIC LAW 94-469— OCT. 11, 1976
90 STAT. 2025
(e) Polychlorinated Biphenyls. — (1) Within six months after Rules,
the effective date of this Act the Administrator shall promulgate
rules to —
(A) prescribe methods for the disposal of polychlorinated
(B) require polychlorinated biphenyls to be marked with clear
and adequate warnings, and instructions with respect to their
processing, distribution in commerce, use. or disposal or with
respect to any combination of such activities.
Requirements prescribed by rules under this paragraph shall be con-
sistent with the requirements of paragraphs (2) and ('A).
(2) (A) Except as provided under subparagraph (B), effective one
year after the effective date of this Act no person may manufacture,
process, or distribute in commerce or use any polychlorinated biphenyl
in any manner other than in a totally enclosed manner.
(B) The Administrator may by rule authorize the manufacture,
processing, distribution in commerce or use (or any combination of
such activities) of any polychlorinated biphenyl in a maimer other than
in a totally enclosed manner if the Administrator rinds that such manu-
facture, processing, distribution in commerce, or use (or combination
of such activities) will not present an unreasonable risk of injury to
health or the environment.
(C) For the purposes of this paragraph, the term "totally enclosed
manner" means any manner which will ensure that any exposure of
human beings or the environment to a polychlorinated biphenyl will
be insignificant as determined by the Administrator by rule.
(3) (A) Except as provided in subparagraphs (B) and (C) —
(i) no person may manufacture any polychlorinated biphenyl
after two years after the effective date of this Act, and
(ii) no person may process or distribute in commerce any poly-
chlorinated biphenyl after two and one-half years after such date.
(B) Any person may petition the Administrator for an exemption Petition for
from the requirements of subparagraph (A), and the Administrator exemption,
may grant bv rule such an exemption if the Administrator finds
(i) an unreasonable risk of injury to health or environment
would not result, and
(ii) good faith efforts have been made to develop a chemical
substance which does not present an unreasonable risk of injury
to health or the environment and which may be substituted for
such polychlorinated biphenyl.
An exemption granted under this subparagraph shall be subject to Terms and
such terms and conditions as the Administrator may prescribe and conditions,
shall be in effect for such period ( but not more than one year from
the date it is granted) as the Administrator may prescribe.
(C) Subparagraph (A) shall not apply to the distribution in com-
merce of any polychlorinated biphenyl if such polychlorinated
biphenyl was sold for purposes other than resale before two and one
half vears after the date of enactment of this Act.
(4) Any rule under paragraph (1), (2)(B), or (3)(B) shall be
promulgated in accordance with paragraphs (2), (3), and (i) of sub-
(5) This subsection does not limit the authority of the Adminis-
trator, under any other provision of this Act or any other Federal law.
to take action respecting any polychlorinated biphenyl.
FIGURE 1. - Toxic Substances Control Act.
4. Electric motors (PCB-filled as used on Joy Manufacturing model CU43
and 9CM continuous miners and 14BU10 loaders): Continued use, maintenance,
disposal, spill cleanup.
5. Separator electromagnets (PCB-filled): Marking, maintenance,
6. Hydraulic and heat-transfer systems (that ever contained a PCB-based
fluid): Marking, maintenance, use, disposal, spill cleanup.
7. Waste oil: Disposal, use.
8. Transportation of any PCB's or PCB equipment.
9. Storage of any PCB's or PCB equipment.
10. Recordkeeping: Required if you have any PCB transformers, more than
45 kg (99.4 lb) of PCB's in containers, or more than 49 large PCB capacitors.
It was the intent of Congress to ban the use of PCB's and thereby prevent
the entry of PCB's into the environment. To continue use of PCB's in those
applications authorized by the EPA, the requirements specified by the regula-
tions must be met. EPA has the authority to enforce these requirements by
performing compliance inspections wherever PCB's are used, including in mines.
Violations of the regulations can result in fines of up to $25,000 per viola-
tion per day. Willful violation of the regulations can result in additional
criminal action against the responsible people, with a possible penalty of a
$25,000 fine and 1 year in jail.
EPA is serious about keeping PCB's out of the environment. Continued use
or handling PCB's or PCB equipment after July 1, 1979, under the authoriza-
tions granted by the EPA, requires compliance with the following general
requirements and the specific requirements that apply to specific kinds of PCB
Recordkeeping (40 CFR 761.45)
Special recordkeeping requirements are specified in Annex VI of the PCB
regulations. Maintenance of these perpetual PCB inventory records is required
for each facility that has in use or in storage —
45 kg (99.4 lb) of PCB's or PCB contaminated material in containers;
One or more PCB transformers;
50 or more large (3 lb liquid) PCB capacitors.
In addition, an annual report must be prepared by July 1 of each year,
summarizing the changes in PCB use during the previous year. EPA will use
these records when it performs compliance inspections, and will consider the
lack of records or discrepancies in the records as evidence of lack of intent
to comply with the regulations. The records will have to be kept until
5 years after the last PCB's have been removed from the facility.
The EPA regulations are very specific as to the kinds of information that
must be kept. Any capacitor that contains 3 lb of PCB's must be considered to
be a "large capacitor" for purposes of labeling, disposal, and recordkeeping.
To estimate the weight of PCB's in a capacitor, assume that 20 percent of the
volume of the can is filled with PCB's weighing 11.4 lb per gal:
Capacitor can volume (cu in) x 0.01 = lb PCB
A "large capacitor" would be any capacitor having a total volume
exceeding 300 cu in.
Marking (40 CFR 761.20)
The EPA requires that special 6-inch-square yellow labels (described in
Annex V of the regulations) be applied to practically everything that has more
than 50 ppm PCB's except small capacitors (less than 3 lb PCB's) and oil-
filled transformers (below 500 ppm PCB's). Labels must be applied to equip-
ment that contains PCB's, including transformers, large capacitors operating
above 2,000 volts, contaminated hydraulic and heat-transfer systems, electro-
magnets, electric motors, cans and drums used to store PCB's and contaminated
material, storage areas, and trucks carrying PCB transformers or more than 45
kg (99.4 lb) of PCB's or PCB-contaminated material. The only exception to
applying the label directly to the item applies to large capacitors mounted on
the top of a power pole or behind a fence at a substation; a single label may
be applied to the pole or fence if records are adequate to identify which of
the capacitors contains PCB's. Large PCB capacitors operating below 2,000
volts do not have to have a label until they are removed from service, but it
would be a good idea to label them now to identify them as PCB items. It is
advisable to keep 10 or 20 extra labels on hand to be applied to drums used to
store used transformer oil, clean up spill material, contaminated rags, etc.
Pressure-sensitive labels meeting EPA requirements may be purchased from
a number of companies, including —
Label Master W.H. Brady Company
6001 North Clark St. 727 West Glendale Ave.
Chicago, 111. 60660 Milwaukee, Wis. 53209
5 This list is for reference only, and does not imply endorsement by the
Bureau of Mines or the U.S. Environmental Protection Agency.
Containers for PCB's (40 CFR 761.42)
Containers used to store liquid PCB's must comply with one of the
(1) 49 CFR 178.80 — specification 5 without removable head.
(2) 49 x CFR 178.82 — specification 5B without removable head.
(3) 49 CFR 178.116— specification 17E.
Any container that meets the requirements described in these specifica-
tions will be marked with D0T-5-, D0T-5B-, or D0T-17E-. There may be addi-
tional markings, but they do not affect the suitability of the containers.
If the liquid PCB's are to be stored in containers larger than permitted
in the above specifications, the following requirements must be met:
1. The containers must be designed, constructed, and operated in compli-
ance with Occupational Safety and Health Standards, 29 CFR 1910.106. The
specification for flammable and combustible liquids is included in Sec-
tion 1910, Title 29 of the Code of Federal Regulations. To obtain a copy,
call (202-783-3238) or write the U.S. Government Printing Office, Washington,
2. Either (a) the container shall be kept in a storage area that meets
the requirements described or (b) a Spill Prevention, Control, and Counter-
measures Plan (SPCC), as described in 40 CFR 112, must be prepared and imple-
mented. (Amendment of SPCC plans by the Regional Administrator, 40 CFR 112.4,
does not apply. The following report describes in detail how to prepare a sat-
isfactory SPCC plan for PCB's; to obtain a copy, call (415-961-9043) or write
the Electric Power Research Reports Center, Box 50490, Palo Alto, Calif.
94303. Electric Power Research Reports Center. Disposal of Polychlorinated
Biphenyls (PCB's) and PCB-Contaminated Materials. V. 2. Suggested Procedure
for Development of PCB Spill Prevention Control and Countermeasure Plans.
V. 3. Example Preparation of a Utility PCB Spill Prevention Control and
Countermeasure Plan. Palo Alto, Calif., 1980.
Any container used to store rags, contaminated soil, or other nonliquid
PCB's must comply with one of the following:
(a) 49 CFR 178. 80— specif ication 5.
(b) 49 CFR 178.82— specification 5B.
(c) 49 CFR 178.115— specification 17C.
(d) Any container larger than the 55-gal size given in the above
specification shall provide as much protection against leaking and be of the
same strength and durability as the containers described.
Containers that meet either a, b, or c above will be labeled either
D0T-5-, D0T-5B-, or D0T-17C-.
With the exception of the specifications from the Occupational Safety and
Health Standards, all of the above specifications are included in Title 49 of
the Code of Federal Regulations, Transportation (parts 100-199). To obtain a
copy, call (202-783-3238) or write the U.S. Government Printing Office, Wash-
ington, D.C. 20402.
Storage (40 CFR 761.42 )
The basic requirement is that PCB ' s be stored in special storage areas in
buildings that are located above the 100-year flood water elevation and that
the storage areas be diked and have impervious floors with no drains. PCB's
put into storage before January 1, 1983, must be removed and disposed of by
January 1, 1984. PCB's put into storage after January 1, 1983, may not remain
in storage for more than 1 year. The items in storage must be checked every
30 days to insure that they are not leaking PCB's.
Temporary storage outside the special storage areas is allowed for cer-
tain nonleaking equipment and containers for a period of 30 days. Nonleaking
large capacitors and drained askarel transformers may be stored adjacent to
the special area until January 1, 1983. The regulations also specify the
types of drums and tanks that can be used to store PCB liquids and contami-
The storage requirements are complicated and probably expensive. Most of
the problems can be avoided by disposal of any PCB's within 30 days after they
are removed from service. However, there are no incinerators presently
approved for PCB liquids, so askarel removed from transformers and other con-
taminated liquids must be stored in compliance with these regulations until
EPA approves an incineration facility.
Spill Cleanup [40 CFR 761.10(d)]
EPA regulations require that all material contaminated with PCB's in con-
centrations above 50 ppm by weight (for example, 1 lb of PCB's in 10 tons of
dirt or other material be picked up, drummed, and disposed of in specially
approved facilities. This is potentially the most expensive provision of the
regulations. The cost of cleaning up PCB spills onto dirt or major machinery
can be high. The cost of cleaning up a PCB spill that has entered the water
can be horrendous. The potential cost of spill cleanup will justify work per-
formed now to limit the extent of PCB spills and may justify replacing PCB
equipment if there is much risk of PCB's entering water from failed equipment.
Immediate response to PCB spills should be based on three major
(1) Minimize human exposure to PCB's: Disconnect the power from electri-
cal equipment to stop the boil-off of PCB's; provide workers with protective
gloves and clothing and, if necessary, breathing apparatus.
(2) Prevent PCB's from entering water: Soak up spilled PCB's with straw,
rags, sawdust, dirt, or anything else that is available; throw up temporary
dikes to minimize the spread of spilled liquid.
(3) After the spill is under control, contact experts to decide on
cleanup and disposal procedures. The PCB labels that are required on all PCB
equipment give the toll-free number of the U.S. Coast Guard National Response
Center (800-424-8802). Personnel at this number will give the names and tele-
phone numbers of EPA personnel at the appropriate regional office who in turn
will be able to give guidance in the cleanup procedure. In the event of a
major spill into water, the Coast Guard will send personnel to supervise and
aid in assessment and cleanup.
You might want to consider distributing a short emergency response guide
within your own organization to mine superintendents, maintenance supervisors,
electrical foreman, etc. A suggested outline is included in appendix A.
Emergency response: U.S. Coast Guard National Response Center, telephone
Supplementary information on cleanup procedures and Federal requirements:
U.S. Environmental Protection Agency, Control Action Division, Washington,
D.C., telephone 202-755-8033.
Information on foam plastic and concrete emergency dikes is available in
the following publication:
U.S. Environmental Protection Agency. Control of Hazardous Chemical Spills
by Physical Barriers. Rept. EPA R2-73-185, 1973; available from National
Technical Information Service, Springfield, Va., PB 221 493 030A.
Information on protective clothing availability is available in the fol-
U.S. Coast Guard. A Survey of Personnel Protective Equipment and Respira-
tory Apparatus for Use by Coast Guard Personnel in Response to Discharges
of Hazardous Chemicals. Available from National Technical Information Ser-
vice, Springfield, Va., ADA 010 110.
PCB spills into water are also regulated under the Clean Water Act.
Rules proposed by the EPA under this act in the February 16, 1979, Federal
Register list 299 regulated hazardous materials, including PCB's. Under these
rules, any spill of PCB's in excess of 10 lb constitutes a "discharge" if the
spill threatens to reach "the waters of the United States." Waters of the
United States do not, at this time, include ground waters, so spills of PCB's
in dry areas such as in some Western States do not constitute discharges as
far as the Clean Water Act is concerned unless there is a chance the dis-
charged fluid can find its way to a stream, river, swamp, or other body of
surface water. The proposed regulations require that any discharge of more
than 10 lb of PCB's into water must be reported within 24 hours to the U.S.
Government in accordance with procedures specified by the Department of Trans-
portation in 33 CFR 153.203. (The proposed regulations also specify separate
fines for spills of PCB's into the water.)
Decontamination (40 CFR 761.43)
The EPA regulations authorize decontamination of containers, such as
steel drums that have been in contact with PCB's by triple rinsing with clean
solvent. The volume of solvent used for each rinse must be at least 10 per-
cent of the volume of the container. Movable equipment used in storage areas
may be decontaminated by swabbing surfaces that have been in contact with
PCB's with a suitable solvent. This same procedure could probably be used to
decontaminate other machinery such as drag lines contaminated with PCB's.
The preferred solvents for cleaning up PCB's are kerosene and light fuel
oil. The workers should be issued protective gloves and other necessary pro-
tective clothing as may be required by the conditions. Protective breathing
apparatus may be necessary in some instances. Used solvents and other contam-
inated materials must be stored in containers that have been marked. This
contaminated material must be stored and disposed of in approved facilities.
Contaminated gloves and other protective clothing should be discarded
into the drums with the other PCB-contaminated solid material. Any PCB's that
get onto workers' skin should be removed using waterless hand cleaner and
paper towels, the paper towels then being disposed of as required for PCB's.
Transportation [40 CFR 761.42, 761.20(b)]
PCB's are not considered a hazardous material under the regulations of
the U.S. Department of Transportation (DOT). Therefore, no special type of
vehicle or placarding is required. However, EPA is planning to promulgate a
comprehensive manifesting system for hazardous chemicals under the authority
of the Resource Conservation and Recovery Act. PCB's will be covered under
Containers used to hold PCB's and contaminated material must meet the
requirements specified by the EPA. Vehicles used to transport PCB's (includ-
ing common carrier trucks and railroad cars) are required to have a PCB label
applied to the outside of the vehicle if they are carrying PCB containers that
contain (1) more than 45 kg (99.4 lb) of liquid having more than 50 ppm on
PCB's or (2) one or more PCB transformers.
It is not required that askarel transformers be drained before thay are
transported. However, the cooling fins on transformers are fragile, and most
of the PCB spills that have resulted in major expensive cleanup efforts have
been caused by damage to askarel transformers during transportation. If an
askarel transformer is drained before it is moved, there will be a greater
chance of damaging the coils; on the other hand, the cost of cleaning up a
spill from a transformer after a truck accident or a loading mishap can be
Disposal (40 CFR 761.10)
Special disposal requirements apply to all PCB equipment and to all mate-
rials contaminated with more than 50 ppm PCB's except for small capacitors
that contain less than 3 lb of PCB's. These small capacitors may be disposed
of in municipal landfills in which the organic wastes are expected to adsorb
and immobilize the PCB's after the capacitor casing rusts through. Solid
spill materials contaminated with more than 50 ppm PCB's must be disposed of
in an approved PCB landfill or special PCB incinerator. Disposal requirements
for PCB equipment follow.
You cannot contract away your responsibility for proper disposal of
PCB's. If there is ever a problem and PCB's are traced to you, it is still
your responsibility. The EPA regulations establish special and stringent
requirements for chemical waste landfills and incinerators used to dispose of
PCB's. To obtain a list of approved facilities, call (toll-free,
800-424-9065, or in Washington, D.C., local 554-1404) or write the Office of
Industry Assistance, Office of Toxic Substances TS-799, U.S. Environmental
Protection Agency, 401 M St., S.W., Washington, D.C. 20460. Contact the dis-
posal facility for prices and special instructions before sending PCB's.
EPA has not yet approved any incinerators for commercial disposal of
PCB's, so all materials required to be disposed of by incineration must be
stored in accordance with the regulations until EPA approves an incinerator.
The term askarel is defined by the 1978 National Electrical Code as "a
generic term for a group of nonflammable synthetic chlorinated hydrocarbons
used as electrical insulating media. Askarels of various compositional types
are used. Under arcing conditions the gases produced, while consisting pre-
dominantly of noncombustible hydrogen chloride, can include varying amounts of
combustible gases depending upon the askarel type." In fact, all of the types
of askarel sold prior to 1979 contained 60 to 100 percent PCB's, the balance
of the mixture usually being trichlorobenzene. The unique advantages of PCB-
based askarel used as a coolant liquid in transformers have been its chemical
inertness and nonf lammability .
Approximately 2 percent of the pad-mounted transformers in use in the
United States contain PCB-based askarel coolant liquid. Askarel transformers
have been used where fires might endanger human life and property. PCB's have
the advantage of nonf lammability , in contrast to mineral oil, the other major
liquid coolant used in transformers. Gaseous coolants are also nonflammable,
but gas-cooled (dry-type) transformers have certain disadvantages when com-
pared with liquid-cooled transformers. Dry-type transformers are generally
more expensive than the liquid-cooled units, and they usually have increased
operating noise levels and a lower capacity to withstand temporary overheating
caused by surges of power in the electrical circuit. Alternative liquid cool-
ants are available, but none has all the advantages of PCB's.
Uses of Askarel Transformers in Mining
The advantages of askarel transformers in mining are the same as in any
application: Askarel fluids are nonflammable. Askarel transformers are, of
course, no longer being produced, but the ones that are in service will be
permitted to remain in service for their occupational lifetimes, which in many
instances could be 30 to 40 years or maybe longer. As will be pointed out
below, none of the alternatives to askarels are direct replacements for
askarel-cooled transformers. Transformers cooled with gases, for instance,
present very little fire hazard, but they are voltage limited because of the
inherent characteristics of gases, and gases simply do not have the heat
capacity of liquids. Liquid-cooled transformers are therefore better where
transformers are likely to be occasionally run at a higher than design load-
ing. The alternative "high-fire-point transformer liquids" are all more
expensive than askarel and do not have the same fire resistance. Oil-cooled
transformers, the mainstay of the transformer industry, are the least costly
of all transformers available, but in applications requiring fire safety, they
must be installed in fire-resistant vaults that can cost several times as much
as the basic transformer.
Askarel-f illed transformers are used in all phases of mining: Under-
ground, in surface installations, and onboard large mobile surface machinery.
Transformers used in mining range in size from 10 to 8,500 kva and contain up
to 3,415 gal of askarel.
The major manufacturers of large surface mining equipment installed aska-
rel transformers on a small portion of their equipment. This was generally
done at the request of the company purchasing the machinery, though Page Engi-
neering used askarel transformers on all of its walking draglines.
Bucyrus-Erie used to provide askarel transformers on electrically powered
draglines, loading shovels, and blast-hole drills. Usually the customer was
being required by its insurance carrier to use a nonflammable transformer
fluid. Askarel transformers, when requested, were mounted inside the machin-
ery in steel rooms that had originally been designed for oil transformers.
These rooms usually had an opening in the floor that would duct the trans-
former fluid to the ground to reduce the fire hazard in the event of a trans-
former rupture; the rooms also contained openings to provide adequate
ventilation. These transformers were 100-to 250-kva single-phase units. It
is estimated that askarel transformers were installed on 5 to 6 machines out
of roughly 400 that were built by Bucyrus-Erie over the past 15 years. 7
Bucyrus-Erie quit suppling askarel transformers around the first part of 1977,
and currently use only mineral oil transformers, but they are investigating
the use of silicone filled units.
7 Telephone conversation with Dick Matusak, Bucyrus-Erie, August 5, 1977.
Marion Power Shovels also supplied askarel transformers in the 100-kva
range on its shovels and draglines at customer request. Askarel-f illed trans-
formers were mounted on only a small percentage of the 1,000 electrically
powered machines that Marion has built. As in the case of Bucyrus-Erie,
askarel-f illed transformers were mounted inside the machine in the fire-
resistant rooms that had been designed to meet specifications for oil-filled
transformers. Marion quit supplying askarel filled transformers during 1975. 8
In contrast with the preceding two companies, Page Engineering, supported
by its insurance company, used askarel-f illed transformers on all the walking
draglines it built before 1977. Each dragline contains a bank of three
single-phase transformers in the 100- to 333-kva range. These transformers
are mounted in cages on steel platforms about 8 ft above the main deck of the
dragline. A major rupture of one of these transformers would result in PCB's
leaking onto the ground underneath the dragline. An estimated 25 of these
machines have been built over the past 10 years.
In addition to the above equipment, an undetermined number of blast-hole
drills built by Robbins Drill Division of Joy Manufacturing used three single-
phase, askarel-f illed transformers.
Equipment that uses askarel transformers is used by a relatively small
number of mines. In some cases, the mining company was required by its insur-
ance carrier to order askarel transformers; thus most or all of the equipment
at these particular mines contains askarel transformers. In addition, it is
not unusual for a company to order its large equipment from a single supplier.
If the supplier were Page, all the draglines at that mine would have askarel
transformers on board.
According to information obtained from Electric Service Co., a trans-
former service company, from comments made during a telephone survey of load
center manufacturers and from information obtained during the mine visits,
there are few askarel-f illed transformers in use underground in coal mines.
All load centers used dry type transformers that have been designed to with-
stand the environment in the mines. When questioned about potential diffi-
culties with dust or dampness in the mines, manufacturers replied that these
conditions do not cause major problems. The few askarel transformers that are
in use in underground coal mines are gradually being taken out and replaced
with dry type transformers.
The relative scarcity of askarel transformers in underground coal mines
is not duplicated in underground metal/nonmetal mines, where the use of aska-
rel transformers is widespread. During visits to three underground mines,
askarel transformers were found in numerous locations in the underground dis-
tribution system, covering all applications from main underground substations
to small units on lighting circuits. The mountings for these transformers
ranged from concrete pads level with a damp mine floor to diked, elevated
a Telephone conversation with Joseph Ivy, Marion Power Shovels, August 8, 1977.
^Telephone conversation with Frank Oslakovic, Page Engineering Co., August 10,
concrete pads. At two of the mines visited, a major askarel leak would easily
find its way into the mine water. This water was being pumped to the surface
where it was being used in ore processing operations and was subsequently
impounded. A major askarel leak in these cases could cause widespread
contamination and would be extremely costly to clean up.
Failure of an askarel transformer accompanied by an internal electrical
arc can vaporize a considerable quantity of PCB's that will then be released
through the pressure relief valve. The National Electrical Code requires that
askarel transformers located in buildings be vented to the outside because of
the potential health problems that could result from worker exposure to high
concentrations of PCB vapors. No such venting is possible with those askarel
transformers used underground, the mines presumably accepting the increased
risk of toxicity as a tradeoff for reduced f lammability.
The extent of askarel transformer use varies from mine to mine. At one
mine only the main underground substations used askarel transformers, and the
remaining transformers were either oil filled or dry type. At a second mine
all the underground transformers were askarel filled as a matter of company
The use of askarel transformers at the surface facilities of underground
mines, both coal and metal /no nmetal, and at the ore processing facilities at
strip mines, is also common. Askarel transformers are used any place where
such use is required by the National Electrical Code, generally any indoor
location where the transformer is not mounted in a fire-resistant enclosure.
The transformers that were observed ranged in size from 50 kva single-phase
units, which contained roughly 40 gal of askarel and fed an auxiliary power
circuit, to 8,500 kva three-phase units that contained 3,415 gal of askarel
and served an electrolytic zinc plant. The only environmental problem
associated with the present siting of these transformers is that in most cases
a major askarel lead would almost certainly find its way through numerous
floor drains into the water system of the surface facility.
Number of Askarel Transformers Used in U.S. Mines
The information in tables 2 and 3 refers specifically to askarel
transformers. Although reference will be made to both askarel transformers
and to PCB transformers, the terms are not synonymous. "Askarel transformers"
contain askarel, while "PCB transformers" includes askarel transformers plus
any other type of transformer that for whatever reason (usually inadvertent
contamination) contains more than 500 ppm (0.05 percent) PCB's. This
distinction and the problems it imposes are discussed in greater detail later
in this publication.
The 2 percent of all transformers cooled with askarels amounts to between
135,000 and 140,000 transformers nationwide. The estimate of the number of
askarel transformers in service in mines was based on data gathered in 20 mine
visits. Table 2 summarized the results of visits in terms of stationary
transformers, machine-mounted transformers, and surface and underground
TABLE 2. - Summary of askarel transformer data gathered during visits to mines
million tons ore
Number of askarel transformers
Machine mounted 1
( 2 )
NA Not available.
Underground transformers for all underground mines.
%o data available fr
Overall estimates of the number of askarel transformers in use by the
various portions of the mining industry have been based on these data and
other information obtained over the period of this study. These numbers are
shown in table 3. 'For the coal industry, the estimates were made by directly
extrapolating the number of transformers at the mines surveyed, based on the
tonnage produced at those mines compared with the tonnage produced by the
entire industry. For the metal/nonmetal industry, the extrapolation was done
based on a comparison of the electrical consumption of the entire industry.
The estimate of the number of transformers includes all mining, crushing,
grinding, washing, drying, and benef iciation operations for each segment of
the mining industry. It is likely that these estimates constitute an upper
bound on the number of askarel transformers actually in service because visits
were made to those mines known to be using askarel transformers.
TABLE 3. - Extrapolated estimates of numbers of askarel
transformers in various mining segments
Number of askarel
How To Identify an Askarel-Filled Transformer
The following methods can be used to determine whether or not a
transformer is cooled by askarel (PCB):
(a) Nameplate data — Most transformers will have intact nameplates con-
taining details on the size of the unit and the weight and volume (usually in
pounds and gallons) of the coolant. In almost all cases where askarel cool-
ants are used, the nameplate will contain the manufacturer's trade name for
askarel. The following trade names for transformer askarel are the ones most
likely to be encountered:
Manufacturers * Trade Name
American Corp Asbestol
Electro Engineering Works NA
Envirotech Buell NA
ESCO Manufacturing Co Askarel 2
Ferranti-Packard Ltd Askarel 2
General Electric Co Pyranol
H. K. Porter NA
Helena Corp NA
Hevi-Duty Electric Askarel 2
ITE Circuit Breaker Co Nonflammable liquid
Kuhlman Electric Saf-T-Kuhl
Maloney Electric NA
Niagara Transformer Corp Askarel 2 EEC-18
Power Zone Transformer EEC-18
R. C. Uptegraff NA
Research-Cottrell Askarel 2
Standard Transformer Corp NA
Van Tran Electric NA
Wagner Electric No-Flamol
NA Not available.
^This list is not necessarily complete. PCB's have been used since
1929, and many companies have gone out of business.
^Generic name used for nonflammable insulating liquids in trans-
formers and capacitors.
(b) If the nameplate does not show one of the above tradenames for aska-
rel and if it is not plainly written on the nameplate that the unit is oil
cooled, then a determination can be made on the basis of the fluid density by
dividing the weight of the cooling fluid by the number of gallons. Fluids
weighing less than 8 lb/gal are definitely askarel. Fluids of intermediate
density should be chemically tested unless the manufacturer of the unit can
identify thev coolant.
(c) If no nameplate data are available (sometimes nameplates become lost
or obscured over the years and cannot be read), then a sample of fluid should
be withdrawn and tested to establish its density. A simple test consists of
using a small amount of water into which a single drop of the fluid 'in ques-
tion can be dropped. The amount of water needed should be kept very small
because if the fluid does turn out to be askarel, the test water will have to
be disposed of in the approved manner. The test is this: If the drop of
fluid sinks in the water, it is askarel; if it doesn't, it isn't.
(d) In many instances where transformers are listed as containing oil,
they may in fact contain small, but significant, amounts of PCB. This small
content of PCB is the result of the past common practice of topping off oil-
filled transformers (after samples have been withdrawn for testing of electri-
cal properties) with spare askarel fluid instead of with transformer oil
(mineral oil). There is no easy way to test such PCB-contaminated oil; a
small sample must be extracted and properly packed and sent to a testing labo-
ratory equipped to measure the PCB content of the fluid. If the oil is found
to contain more than 500 ppm PCB, the transformer will have to be treated as
if it is an askarel transformer in order to be in full compliance with Federal
Oil-filled transformers may be assumed to be "PCB-contaminated trans-
formers" unless it is known that the oil contains more than 500 ppm PCB's.
EPA Requirements for PCB (Askarel) Transformers
Definition : PCB transformers are those liquid-filled transformers in
which the liquid contains more than 500 ppm PCB's. (Note: PCB transformers
mounted on railroad locomotives and multiple-unit electric commuter cars are
covered by different requirements.)
Manufacture, import, and sale of new PCB transformers : Banned
Use : Continued use of nonleaking PCB transformers is authorized
Diking : Not required, but you are responsible for cleaning up all
Marking : A large (6-inch-square) label must be applied to each PCB aska-
Recordkeeping : The central PCB records must contain the identity and
location of each PCB askarel transformer; the weight of PCB's contained in
each unit; the date each transformer is removed from service, placed into
storage, and shipped for disposal; the storage location and disposal location
for each transformer removed from service; and the name and address of the
purchaser of each PCB transformer that is resold.
Resale of used nonleaking PCB transformers by user : Authorized.
Servicing : Authorized provided the coils are not removed and there is no
change in ownership of any PCB's. 10
Rebuilding : Banned (coils may not be removed from the tank).
Retrof illing (substitution of other liquid for PCB's): Authorized if
there is no change of ownership of PCB's. 11 The transformer must still be
considered a PCB transformer as long as the concentration of PCB's in the
liquid is above 500 ppm by weight (1 lb PCB's in 2,000 lb of liquid). A
retrofilled transformer may no longer meet the definition of an askarel trans-
former established by the National Electrical Code and may therefore have dif-
ferent code restrictions on its use.
Processing of used PCB askarel for reuse : Authorized provided there is
no change in ownership of the liquid. 12
Sale of new or reclaimed PCB askarel: Banned.
Storage of new or reclaimed askarel : Must be in special storage areas
meeting the EPA requirements.
Disposal : Drain liquid PCB askarel into approved containers. Fill
transformer with kerosene or fuel oil, allow to stand for at least 18 hours,
and drain into approved containers. Seal up drained transformer and dispose
of in an approved chemical waste landfill. Dispose of liquids in an approved
chemical waste incinerator (at present, store until an approved incinerator
becomes available). Storage beyond 30 days to be in special area.
Scrap recovery of failed PCB transformers : Banned.
Spill cleanup : All material contaminated with more than 50 ppm PCB's
must be picked up and disposed of in facilities approved by the EPA.
10 Unless the seller of PCB's has applied to the EPA for an exemption from the
ban on "distribution in commerce" of PCB's and EPA has granted the
exemption. Change of ownership for purposes of approval disposal is
^See footnote 10.
12 See footnote 10.
13 See footnote 10.
Precautions for Continued Use
As pointed out above, there are about 3,400 PCB askarel transformers
presently in use in the U.S. mining industry. The EPA regulations will allow
these transformers to remain in service until they fail, provided the special
PCB label is applied to each unit and the required records are kept. However,
the EPA regulations require special disposal of any material that is contami-
nated by PCB's spilled or vented from any transformer, whether caused by acci-
dental damage to the transformer or by electrical failure of the unit. The
resulting cleanup costs can be very high if large quantities of soil are con-
taminated or, particularly, if PCB's enter any sewer, stream, or other water.
In addition to the costs incurred in cleaning up spilled PCB's, the owner of a
failed transformer may be subject to stiff fines for improper disposal of
PCB's if it is not possible to recover all the lost fluid.
The risk of large, uncontrolled PCB spills can be minimized by analyzing
the possible risks associated with each PCB askarel transformer and by taking
steps to contain the uncontrolled spread and loss of PCB's from the unit.
This section describes a number of methods that can be used to secure trans-
formers against spills, including:
Plugging of water drains
Fences and vehicle barriers
Emergency foam packs
Special problem transformers
Significance of Water
When PCB's leak into the environment from transformers or from any
source, the already widespread PCB pollution problem becomes aggravated.
Recovery or cleanup of spilled PCB's is usually expensive, partly because the
disposal costs are high and partly because special effort must sometimes be
expended, as in cases where PCB's spill into water.
When PCB's spill onto land (that is, onto soil or dirt) the cleanup pro-
cedure consists primarily of removing the contaminated soil and disposing of
it in an EPA-approved chemical waste landfill. This can be expensive. The
amount of soil that has been removed following spills has been tens of thou-
sands of barrels, which after transport and burial costs, can easily run to
costs of more than $100,000.
Spills into water, however, are vastly more complex and therefore more
expensive. Even spills into nonf lowing lakes or swamps, as opposed to rivers
or streams, result in extreme cleanup costs because of the dredging operations
that are invariably necessary and because of the greater volume of waste mate-
rial (for example, earth and sediment) that must be handled, packaged,
shipped, and buried. In rivers where the moving water can both aggravate the
cleanup operation as well as spread the PCB's that are stirred up from the
bottom sediments during the dredging operations, cleanup costs can be high
and, at the same time, substantial environmental pollution can still result.
In one instance in Washington State, an askarel transformer containing about
250 gal of fluid was accidentally dropped on a dock and leaked into a river.
After all the cleanup operations, it was calculated that only about 7 percent
of the askarel was recovered, and the cost was close to half a million
Cleanup of spills that occur on land can be especially costly if the
spill threatens to contaminate groundwater that is used for drinking. Vast
amounts of soil may have to be removed to approved chemical waste landfill
facilities, and costly tests must be performed to insure that the contamina-
tion has been contained.
Thus the presence of water near a leaking transformer is an important
consideration in deciding how to best manage a PCB askarel transformer.
In general, the objective in the securing of PCB transformers is to
insure that any large leak of fluid will be contained within a specified area
away from access to water of any kind (including sewage water and drainage
systems that connect to either sewage systems or to any type of water body
including groundwater). It is expected that in most instances (at least 3 out
of 4 times) it will be feasible to either build a dike around the transformer
and switch gear assembly or to effectively dike the entrance ways to the shel-
ter or rooms that contain the units.
In all instances, the inspector or engineer who makes the decision on how
to deal best with a given transformer should be on the lookout for all possi-
ble methods by which fluid can escape into the environment. For outdoor
transformers, sheltered or unsheltered, the proximity of soil and access to
water by way of floor drains, ditches, or whatever method, should be noticed
and taken into consideration in establishing both the priority and the type of
confinement for a given transformer. For indoor and underground transformers,
drains should be pinpointed and should be plugged and sealed. Otherwise,
efforts should be taken to insure that spilled fluid will be restricted from
access to the water.
For all transformers, spill confinement measures should include assurance
that transformer mounting pads are not cracked or broken, that adjacent walls
that may become part of proposed spill-confinement system (especially walls
made of porous materials such as cinderblock) are well sealed near the floor,
that the interface between the walls and floor (this is called the wall-floor
interface) is sealed, that there are no holes in the floor such as conduit
access holes through which fluid can drain, and that there are sufficient bar-
riers and/or fences to protect the unit from damage from vehicles (automobiles
and lift-type trucks) and from damage by people who may be moving or working
in the area.
It is not felt that it will be necessary to use the following decision
guide in order to effectively analyze all transformer settings for spill
potential and optimum spill confinement measures. It is likely that whoever
uses this guide will, by doing so, quickly learn to see the points that need
to be considered without having to refer to the guide.
Decision Guide Questions and Considerations
1. If the PCB askarel is located on the surface inside a building or
outside, is there any way that fluid leaked from the unit could find its way
to either a water drain (such as a sewer or a gutter leading to a sewer) or
directly to water (for instance, by running downhill and into a stream or
swamp or river)?
If so, such units should be given priority in spill prevention mea-
sures. If not, the unit should still be secured against leaks, though the
urgency is not as great as that of units located with access to water.
2. If the transformer is located below ground, or even simply below
grade, in a location from which groundwater must be continually pumped, is
there any way that fluid leaked from the unit could find its way into the
Since groundwater is usually pumped out of mines, PCB contamination
could easily be spread to larger volumes of water and soil, and if the water
is used in ore processing, it could also contaminate the ore and processing
plant. Transformers in such situations should be given priority in spill pre-
3. In some instances PCB transformers are located in rooms or in alcoves
that appear to be secure against the loss of fluids to either water or soil;
if this is the case, are there curbs or diking either around the transformers
or across the entrance ways to the transformer rooms so that the units are
completely secure against uncontrolled loss of fluid?
4. In cases where transformers are situated in rooms with porous cinder-
block walls, are those walls sealed with either grout type sealers or with a
heavy type of paint that is not soluble in chlorinated hydrocarbon solvents
such as PCB and trichlorobenzene?
5. If the transformer is otherwise secured against leaks, is the mount-
ing pad or the floor of the transformer room free of cracks? Cracks that look
like they would not prevent the loss of fluid should be grouted and painted
with solvent resistant paint that will serve the dual purpose of sealing
smaller cracks not grouted and of sealing the pad against water absorption
that in cold places can cause freeze fracturing of the concrete.
6. Is the transformer in a location where vehicular traffic might be a
hazard? For instance, is it located near to a driveway or next to a parking
lot? If so, a vehicle barrier might be useful, expecially if the unit is
located where a body of water might be threatened by a loss of fluid.
7. Is the transformer located near machinery that might throw projec-
tiles with sufficient energy to damage the unit? Is the transformer located
in a place where forklift vehicles might accidently run into it or snag the
heat exchanger or some other part? If so, fences or vehicle barriers might be
necessary to provide protection, unless it is reasonably feasible to either
relocate the transformer to a safer place or to replace it with a non-PCB
8. Is the unit mounted on unwelded steel plates (as might be the case
if the unit is platform mounted), mounted on a second story, mounted in a
mobile machine, or mounted on some other type of surface that might be
extremely difficult to seal against fluid loss? Such a unit could be tempo-
rarily removed while the mounting surface is sealed. If the transformer does
not present an immediated threat to water or to personnel and would not pose
any great difficulties in a cleanup should a spill occur, then no securing
measures need be taken.
9. If the unit is pad mounted, is there room for installation of a dike
on the edge of the mounting pad? If not, and if some kind of spill protection
is needed, either the pad could be extended and a curb installed as part of
the extension or a berm of asphalt, concrete, or clay could be built around
10. If the unit is mounted near a wall that will be part of the spill
containment barrier, is the wall of nonporous material such as concrete or
sealed cinderblock and is the wall-floor interface tight against fluid loss?
11. If the transformer is in a special room, alcove, or vault, is this
area used as storage space, for example, for brooms and other building mainte-
nance materials? If so, and if there is no other better storage place for the
stored materials, it might be best to put a dike around the transformer itself
rather than to secure the room as a whole to prevent additional cleanup
expense from contaminating extra material.
12. If the transformer is in a special room, alcove, or vault, are there
also drains in the room that cannot be sealed and removed from service because
they are needed to remove water from other systems sharing the room with the
transformer (for example, an air-conditioning system)? If so, the transformer
rather than the whole room will have to be diked against the possibility of a
13. If the room is used for nontransformer-related activities, is the
unit sufficiently protected against the potential for mechanical damage?
14. If the unit is located outside and is already adequately diked
against the possibility of fluid loss, is there an allowance for the removal
of rainwater by a properly designed water-only drainage system? The design of
a water-only drainage system that can be built from exiting plumbing hardware
is included as appendix B of this report.
15. Is the unit old or does it appear to be old? If so, this may be a
consideration in whether or not to replace the unit. There are commercial
transformer service companies that are experienced in the testing of trans-
formers to find out whether or not they are in condition to continue in
16. Is^there any evidence of an active leak from the transformer? If
so, and if it is due to corrosion or a broken or cracked weldment, the unit
should probably be replaced. Otherwise, arrangements should be made to repair
the unit, especially if it is located near water or a path to water and if
there are no immediate plans to secure the unit against fluid loss. (NOTE:
Approximately 10 percent of pad-mounted askarel transformers show some evi-
dence of leaking.) If the unit has to be replaced, is its setting suitable
for the installation of an oil-filled transformer? That is, does the setting
satisfy the NEC requirements for the installation of oil-filled transformers
(indoor or outdoor)? If not, the new transformer will either have to be of a
fire-safe design, or an oil-filled transformer will have to be installed in a
A dike is the most effective, aesthetically appealing technique for con-
taining a potential spill. It is also among the least costly of spill preven-
tion measures, expecially when compared with the alternatives of retrofilling
and relocation discussed below.
A suggested steel dike system shown in figures 2 through 5 consists of
steel angles (measuring 3.5 by 6 inches) that are bolted to the periphery of
the mounting pad. The seal between the dike and the pad consists of a gasket
of 3/8-inch-thick closed cell neoprene foam rubber. The corners of the dike
are bolted together by means of 2- by 2-inch steel angles.
6-inch-high angle steel with 3.5 foot
base and 5/16-inch wall thickness
Corner joint of
2- by 2- by 1/4-inch
Typical transformer and switch gear on con-
crete mounting pad with steel dike installed.
An alternative to this
steel dike system is a con-
crete, curb-type dike. How-
ever, the concrete dike may
be more costly to install
and, since it would have to
be at least 5 inches wide to
be sufficiently durable,
would require more room on
the periphery of a trans-
former pad than the steel
dike. In cases where the
mounting pad is small, this
can be an important consid-
eration. Also, the curb-
type dike would slightly
inhibit the accessibility of
the transformer for mainte-
nance operation, moreso than
the steel dike.
"O * CJ
a o ;=
to 5 +i
*• 2 a
•>- £ -a
5 g 5 £ 1 1
00 *+« oo
0) C 0) JS
„ T5 E a
0) in « ■-
o) c » 75 t S S
n £ n * » 2
J 4) 0) ; = *■
is .£ <0 «- "O CM
c "5 '
Dikes can be installed in both indoor and outdoor locations. In outdoor
locations, however, especially in parts of the country where rainfall is
excessive, provision must be made for water drainage in order to minimize the
corrosion hazard to the transformer-related switch gear and casings. A water-
only drainage valve, along with the parts specifications, is shown in fig-
ure 6. It will permit the passage of 3 gal/hr of water (when submerged 3
inches deep), but will close if the level of askarel approaches the level of
the drain opening.
Clean this surface and coat with
epoxy joining compound immediately
before pouring cement
3/4" to 1" re-bar
_ Q _ 0_ _
FIGURE 7. - Schematic diagram of basic parts and dimen-
sions of an extended mounting pad: A, exca-
vation and re-bar location; B, cross section
of extended pad.
Curb-type dikes can
most easily be installed in
those instances where the
mounting must be enlarged
because of insufficient room
even for the steel dike.
Figure 7 shows the typical
requirements for the
enlargements of a mounting
and the installation of a
A berm is simply a
mound of earth or asphalt
surrounding an outdoor
transformer. A berm, espe-
cially an earthen one, would
take up much more room than
a steel dike, and if porous
enough to allow the drainage
of rainwater, would also be
too porous to give maximum
protection against high
cleanup costs in the event
of a PCB spill. On the
other hand, it would be dif-
ficult to install an effec-
tive water-only drainage
system in a berm if the berm
were adequately waterproofed
with a lining of bentonite
or some other impermeable
Asphalt berms con-
structed on asphalt or con-
crete surfaces that surround
a given transformer mounting
might be a low-cost alternative to dikes, but they can restrict accessibility
of the transformer and are not as aesthetically appealing as a dike.
In cases where there is a moderate problem of water accessibility to a
potentially leaking transformer, and where the transformer is in a location
where vehicular damage is a possibility, such as near a parking lot or street
or driveway, a berra could provide both security against leaks and protection
Fences and Vehicle Barriers
It is probable that a small number of PCB transformers will be found in
locations where the threat of damage from moving vehicles should. be taken into
consideration (for instance, in locations where forklift type vehicles are
commonly used, either indoors or outdoors, and next to parking lots and close
In some cases, chain-link fences will provide adequate protection against
lightweight freight vehicles, but usually where vehicle damage to transformers
is possible, heavier protection such as that depicted schematically in fig-
ure 8 is advisable. The simple pipe-type barriers can be installed with
1.5 feet if surrounded by
concrete or asphalt pavement
5-inch-diameter steel pipe,
1/4-inch wall, concrete filled
3 feet if set in concrete
but surrounded by sod
Vehicle barrier suitable for protection of an askarel transformer located in a park-
ing lot or next to a street.
relatively little effort and cost, and in many instances, one pipe of suffi-
cient diameter will provide adequate protection.
Curbs and Doorway Dikes
Transformers, PCB or otherwise, are often mounted in special transformer
rooms. Whether the room is inside a larger building or is a free-standing
structure, the least costly method of securing the transformers against PCB
loss is often to install a dike or concrete curb at entrances. The only cases
where an entrance sill may not provide adequate protection would be where
there is a drain in the room with the transformer that cannot be plugged (say,
because the room is shared with an air-conditioning unit that must be provided
a drain for the runoff of condensation), or where the floor or walls will not
provide a tight sealing barrier against fluids. Walls of special enclosures
are often made of unpainted cinderblock built onto concrete mounting pads. In
this case, both the walls and the interface between the wall and floor must be
sealed with a material that is only minimally soluble in chlorinated hydrocar-
bons (PCB's and triclorobenzene). This can be done by grouting with cement or
other inorganic material and then painting.
Emergency Foam Packs
Possibly the most cost effective means of spill control — but not of
prevention — is with the use of emergency foam packs. These are back-mounted
units capable of dispensing up to 70 cu ft of urethane foam that can be used
to form a fluid barrier very rapidly. However, there are certain disadvan-
tages to these units, including the need to keep at least one person in train-
ing and on call in the event of a spill. Also, the urethane foam will not
adhere well to wet surfaces nor will it provide a good fluid barrier if
located on porous or sandy soil. On concrete or asphalt, urethane should make
an effective instant dike. The problems with wet surfaces have been studied,
and some solutions have been found. For additional information the interested
reader is referred to the following publication:
U.S. Environmental Protection Agency. Control of Chemical Spill by Physical
Barriers. Pub. EPA-R2-73-185, March 1973; available from National Techni-
cal Information Service, Springfield, Va., PB 221 493 OBA.
Instances will probably arise where no set of preestablished procedures
will apply to a special-problem transformer. For instance, sometimes in order
to conserve floor space, indoor-mounted transformers are mounted on raised
platforms 10 or 12 ft or more above the floor, often on a platform of steel
plates that are not welded together to form a liquid-tight seal. This is com-
mon in draglines. In such a case, there is no way to dike and to seal the
platform against fluid loss without temporarily raising the transformer and
then welding the platform plates together. But the effort in temporary
removal of an askarel transformer is not much less than the work required to
relocate the unit either on the floor (on concrete, diked) or outside the
building. A similar effort could replace the unit with a different fire-safe
transformer or with an oil-filled transformer mounted outside. In other
words, the amount of effort to secure a transformer against fluid loss to
adjacent work areas and to the environment at large might be more than is jus-
tified by the probability of a major leak. It might be more effective in the
long run, if water or vast amounts of porous soil are not threatened by a pos-
sible leak, to leave the PCB unit in service without precautions; if water is
a problem, it "might be best to replace the unit rather than to secure it
Most transformers can be readily secured against fluid loss, but protec-
tion of those that are resistant to easy solution will have to be decided by
comparing cost of securing the unit against fluid loss or removing it to a
better location versus the potentially high cleanup costs should a leak
Mobile Mining Machinery
Transformers are used on electrically powered draglines, shovels, and
blasthole drills to reduce the incoming high voltage to the levels required by
the drive motors. In most instances, mobile mining machines have been
designed to safely use oil-filled transformers. However, several mining com-
panies have asked that machines be delivered with askarel transformers, and
the manufacturers have complied.
There appears to be no general method for securing onboard askarel trans-
formers against loss of fluid. In some instances there is sufficient room to
allow the installation of transformer dikes; in some cases, however, the sim-
ple installation of a dike would not be sufficient; for instance, the mounting
surfaces often consist of a floor made of steel plates that are butted up
against each other without being welded or sealed. Welding of mounting sur-
faces under transformers would require the temporary removal of the trans-
former, an undertaking that would be almost as costly and time consuming as
replacement of the units with nonaskarel units.
Most mobile mining machinery that contains PCB transformers is used in
surface applications. The loss of PCB fluid from an onboard transformer
might be difficult to clean up if it runs into the complex portions of the
machinery, but the loss of fluid to the ground would probably be unaggravated
by the presence of water in most instances. The cleanup procedure would con-
sist of decontaminating the machine and the containers and of disposal of
earth and soil.
If anything general can be said about the precautions that can be taken
with respect to askarel transformers on mining machines, it is that the indi-
vidual mining companies will probably have to use some subjective measures to
determine whether the cost of securing their mobile-mounted askarel trans-
formers against leaks is likely to be less than the cost of fines, penalties,
and cleanup costs in the event of a transformer failure.
Relocation of Transformers
It has been noted in many transformer surveys, at mines as well as in
other industries and operations, that not all askarel transformers are located
in places where electrical codes or safety considerations require their use.
In such cases, especially where a fluid loss from an askarel or PCB trans-
former could reach water or otherwise cause local or environmental damage, the
simplest and securest solution is to replace the PCB transformer with an oil-
filled unit and to relocate the original transformer in a site known to be
secure from leaks. It might be feasible in a small number of cases to simply
exchange two transformers, location for locations, and to totally eliminate
any other PCB securing measure.
Retrofilling is the replacement of the PCB askarel fluid in a transformer
with non-PCB fluid. Askarel transformers located in places where fire hazard
is a consideration can be retrofilled with silicone fluid or with the new
high-fire-point hydrocarbon fluids that are available. However, retrofilling
is expensive and a single retrofill does not usually reduce the concentration
of PCB's to below 500 ppm.
Typical commercial costs for field retrofilling of askarel transformers
are $30 per gal of capacity of the transformer, and this does not include the
cost for storage of the PCB fluid removed or of the solvent fluids used to
flush the transformer at the time of retrofill. (PCB storage is necessary
until approved PCB incineration facilities become available; cost of disposal
is expected to be high because it must include the cost of shipment by an
approved method; the actual cost of incineration will probably be on the order
of several dollars per gallon of PCB's.) Retrofilled transformers must be
marked and handled as PCB transformers unless the concentration of PCB's has
been reduced to below 500 ppm. A transformer must be retrof illled a^t least
3 times to get the concentration of PCB's to less than 500 ppm. Successive
retrofills should be at least 18 months apart.
The major advantage of retrofilling is achieved only if the concentration
of PCB's is reduced to below 500 ppm by repeated replacement of the liquid.
Once the concentration of PCB's has been reduced to this level, the trans-
former may be considered a PCB-contaminated transformer and may therefore be
rebuilt if it fails. If a PCB askarel transformer is in a critical applica-
tion and the time saving achieved by rebuilding rather than replacing the unit
when it fails offsets the cost of multiple retrofilling, this procedure might
be justified. However, once the unit is filled with oil, silicone, or high-
fire-point transformer liquid, the risk of fire is increased, and although the
total amount of PCB-filled units in the unit is decreased, the same cleanup
requirements exist as for PCB-filled units if the concentration of PCB's is
above 50 ppm.
The technology for reducing residual PCB levels in retrofilled trans-
formers is rapidly being developed, and the supplier of the liquid should be
contacted to determine the cost and feasibility of achieving the 50 ppm level
of PCB's in retrofilled transformers. The companies most active in this field
For Hydrocarbon fluids: RTE Corp.
1900 East North St.
Waukesha, Wis. 53186
For silicone fluids: Dow Corning Corp.
Midland, Mich. 48640
Non-PCB Replacement Transformers
New PCB askarel transformers have not been manufactured in the United
States since 1978, and EPA regulations prohibit the manufacture of additional
new PCB units or the rebuilding of existing units. Therefore, it will be
necessary to replace every existing PCB askarel transformer, either when it
fails or because there is too great a risk of uncontrolled PCB spills and no
adequate way to dike or protect the transformer.
There are a number of alternatives to the use of PCB askarel trans-
formers, but each type is characterized by different tradeoffs of fire safety,
overload capacity, and initial price. Most existing large non-PCB trans-
formers are filled with transformer oil, which is a refined petroleum oil with
viscosity and flammability characteristics comparable to those of SAE 10 motor
oil. Oil-cooled transformers are the least costly units available for instal-
lations where the potential fire hazard presented by the oil is not a problem.
Askarel-f illed transformers have almost all the advantages of oil-cooled
transformers, plus they are the most fire safe of any kind of liquid-filled
transformer. (The disadvantages of askarel compared with oil, aside from the
obvious ones of the recently recognized toxic and environmental hazard, are
such minor considerations as the higher solvency strength of askarel on the
insulation components of transformer windings, plus slightly lower dielectric
strength than oil, and a tendency for the askarel to form corrosive HC1 under
conditions of internal arcing or even during corona discharge; the latter
effect results in a more stringent maintenance program for askarel trans-
formers than for oil transformers.)
The alternatives to askarel transformers are listed, described, and com-
pared below. No one of the alternatives has all of the advantages of askarel
transformers, all cost slightly to significantly more than askarel trans-
formers, but none present the environmental hazard with PCB's. Some
alternatives have special advantages possessed by neither oil nor askarel
transformers. The attributes of the different types of non-PCB alternatives
are given below; they are compared on an installed cost basis, and a simple
decision guide is supplied at the end of this section.
Characteristics of Non-PCB Replacement Transformers
The major disadvantage to mineral oil is its f lammability. Transformer
mineral oil has a flash point of 145° C, and if an arc occurs within the
transformer, the breakdown products will be hydrogen and methane, which are
also flammable. Detailed records of such failures are maintained by the
electrical industry. Fire underwriters do not approve of the use of oils and
other flammable liquids for indoor applications; where oil-filled transformers
are not specifically prohibited as onsite replacements for askarel-f illed
units, the National Electrical Code imposes certain restrictions upon their
mode of installation.
If safety were not a consideration, there would be no reason why
oil-filled transformers could not be used in all applications. Askarel-f illed
transformers cost about 1.3 times as much as oil-filled units of the same
capacity, and thus most users prefer the oil type where possible. The
oil-filled transformers are the same size as the askarel units, and they are
considerably lighter in weight. In addition, mineral oil has somewhat better
heat-transfer characteristics than does askarel, and an electrical arc in
mineral oil results in breakdown products that are noncorrosive.
Oil-filled transformers can be used in these applications only if they
are suitably isolated from flammable structures or if these structures are
suitably safeguarded against fires. Where transformers are located outside
the building or mine they service, however, the low-voltage power must be
brought into the building via cables or insulated buses, incurring additional
energy losses due to Joule heating in the additional low-voltage transmission
The National Electrical Code specifies the vault requirements for
oil-filled transformers in indoor locations. Building a fire-resistant vault
can double the installed cost of the transformer.
There are apparently no Federal regulations that prohibit the use of oil-
filled transformers in underground mines. Although some mines have removed
all oil-filled transformers from underground installations because of the fire
hazard associated with the possible loss of hundreds of gallons of hot oil,
other mines have used oil-filled units underground for years with no problems.
Adequate safety underground can be achieved by installing an oil-filled trans-
former in a vault that is equipped with automatic dampers on the ventilation
openings and automatic fire supression systems that would flood the vault with
carbon dioxide or Halon 1301 gas in the event of a fire. An extensive discus-
sion of the fire protection recommended for use with underground oil-filled
transformers is included in the following report:
Buckley, J. L. , B. G. Vincent, and R. G. Zalosh (Factory Mutual Research).
Improved Fire Protection for Stationary Underground Equipment. BuMines
Open File Report 27-78, May 1976, 163 pp.; available from National Techni-
cal Information Service, Springfield, Va., PB 280 136/AS.
Silicone Transformer Liquid
All liquid-filled transformers have better sustained overload capacity
and short-term, high overload capacity than do dry type transformers. The
greater heat capacity of liquids compared with air and other coolant gases
used in transformers is the reason for this greater overload capability. The
fire-resistant alternatives to askarels are mainly silicones and high-
fire-point hydrocarbons of the paraffinic variety. A discussion on high-
fire-point hydrocarbons follows.
Silicone-f illed transformers are filled with low-viscosity polydimethyl
siloxane liquid. Silicone fluids are nontoxic, have low flammability (though
not quite as low as PCB's), and low solvency strength (which means that trans-
formers filled with silicone can be expected to have very long service lives).
The disadvantages of silicones are (a) even though the material is referred to
as "low viscosity," silicone is more viscous than either oil or askarel, which
means that silicone-filled transformers must be slightly larger than trans-
formers of equivalent power capacity filled with askarel or oil; (b) on a vol-
ume basis, silicone fluids cost about twice as much as askarel; (c) when
silicone does burn, it releases clouds of amorphous silica that may create
visibility problems; and (d) when used as a retrofill fluid, the poorer heat-
transfer characteristics of silicone relative to askarel require the derating
of the transformer by about 15 percent if the unit is likely to be run contin-
uously at close to its original rated temperature.
Silicone-filled transformers are not recommended for use in underground
coal mines because silicone vapors will gradually deactivate methane detec-
tors. Silicone liquids are also powerful defoamers, so large spills of trans-
former silicone liquid onto ore that will be treated by floatation or into the
water of a floatation plant may disrupt the operation of the process.
High-Fire-Point Transformer Liquids
The 1978 edition of the National Electrical Code has a new specification
for high-fire-point liquid insulated transformers that reads: "Transformers,
insulated with a nonpropagating liquid approved for the purpose, having a fire
point not less than 300° C shall be permitted to be installed indoors or out-
doors. Such transformers installed indoors and rated over 35,000 volts shall
be installed in a vault."
High-fire-point fluids for transformers are essentially of three varie-
ties: (1) Natural, that is, derived from natural hydrocarbon fluids by refin-
ing out everything but certain molecular species, uaually the long-chain
paraffinic molecules; (2) synthetic hydrocarbon, that is, built up out of
simpler molecular species into long-chain paraffinic molecules; and (3) sili-
cones. The hydrocarbon products are roughly the same, just derived by differ-
Factory Mutual has published the following installation and protection
guidelines for transformers that contain high-fire-point liquids:
Factory Mutual Engineering Corp. Less Flammable Transformer Fluids. Data
Sheet 5-4S/14-8S, October 1979; available from Factory Mutual Engineering
Corp., 1151 Boston-Providence Turnpike, Norwood, Mass. 02062, telephone
The minimum allowable distances between the edges of the diked area and the
adjacent walls and the minimum allowable ceiling height are specified based on
the size of the diked area and the rate of heat release from a pool fire of
each specific transformer liquid. Factory Mutual has measured heat release
rates from the various liquids that are commercially available, and this
information is included in the Data Sheet.
There are a number of questions not yet satisfactorily answered concern-
ing the use of the high-fire-point transformer liquids. The most important
question concerns the realism of the test conditions. It has been suggested
that catastrophic arcing followed by case rupture is a relatively unusual mode
of transformer failure and that a more frequent problem is prolonged minor
arcing that generates flammable gases from the breakdown of transformer fluid.
The flammability of unused liquids may not be a reliable indication of their
relative safety under actual transformer operating conditions.
The fire point of the synthetic hydrocarbon high-fire-point fluid is
about 310° C; for the refined high-fire-point hydrocarbon it is about 312° C;
and for silicone it is 360° C. The high-fire-point of the paraffinic hydro-
carbon fluids is a result of the relatively high molecular weight of the
hydrocarbon material. The inherent disadvantage of the high molecular weight
is higher viscosity and thus lower heat-transfer capability than either ordi-
nary mineral oil or askarel. The major advantages of the high-fire-point flu-
ids are their low price relative to silicone and askarel and their inherent
Open Air-Cooled Transformers
Transformers can be built without the use of a liquid cooling medium.
One type of dry transformer that is quite successful under limited conditions
is the open air-cooled transformer. In this design, the required cooling is
provided by air that passes through the transformer as a result of either
thermal convection or forced fan circulation. In those sizes where air-cooled
transformers are available, they are about equal in price to askarel-f illed
transformers of the same kva rating. However, the following limitations gov-
ern the successful use of open air-cooled transformers and prevent them from
being considered for many applications using askarel-f illed transformers.
Heat Capacity : The power drawn from a transformer usually varies over a
fairly wide range. The rating of a transformer is basically governed by the
power it can handle continuously without overheating. If a liquid-filled
transformer is operated at overload conditions for a short period of time, the
liquid will act as a heat sink, absorbing the excess heat produced in the
transformer without a rapid increase in temperature. The result of this ther-
mal inertia is that liquid-filled transformers can operate at outputs of up to
200 percentr of rated capacity for a period of 1 to 2 hours without being
An air-cooled, dry-type transformer does not have this heat sink availa-
ble and is limited to operating at a maximum service rating near its contin-
uous rating. Where the current drawn on the transformer does not vary greatly
during the day, this limitation is no problem. However, in most cases the
variation in load would require that a dry transformer be sized 20 to 30 per-
cent greater in capacity than a liquid-filled transformer for the same
Dielectric Strength : The liquid coolant in a liquid-filled transformer
also provides a significant level of electrical insulation between the various
current-carrying components within the transformer. Air has a much lower
dielectric strength, and open air-cooled transformers are limited to a maximum
voltage of 25 to 40 kv. The problem of electrical insulation is even more
severe if the open air-cooled transformer only operates intermittently. When
the transformer is operating, the heat generated within the windings keeps
their insulation dry and maintains a high dielectric strength. However, when
the transformer is not operating, the coils cool to ambient temperatures and
the insulation can absorb moisture from the air, which reduces its dielectric
strength. Therefore, an open air-cooled transformer must be carefully dried
before being put into service after each time it has been allowed to cool.
One final problem with dry air-cooled transformers is due to the tendency
of dust to be attracted from the air to the coils by electrostatic attraction.
This dust can build up in the coils, which blocks the flow of air and causes
overheating, or the dust can form conductive paths that short circuit the
Dry, open air-cooled transformers are generally limited to dry, clean
locations where the load requirements are fairly even and constant, and where
the maximum voltage does not exceed 30 kv.
Sealed Gas-Filled Transformers
A dry transformer can be provided complete protection from environmental
effects by sealing it is a pressure-tight container and using an inert gas as
the coolant. Gas-filled sealed transformers have the same overload limita-
tions as dry air-cooled units, but better control of the insulating media
raises the maximum achievable voltage to levels available with liquid-filled
Several different gases have been used as the coolant in sealed gas-
filled transformers. The commonly used gas in the United States is hexafluor-
oethane (C 2 Fe). Although chlorof luorocarbons are regulated by the EPA, the
use of this gas in transformers will probably not be affected by the regula-
tions. Nitrogen and sulfur hexafluoride have also been used successfully as
transformer coolants in certain applications.
Because the inert gas increases in pressure when heated, a gas-filled
transformer must be enclosed in a heavy pressure vessel housing. The pressure
vessel increases both the size and weight of the gas-filled transformer com-
pared with that of open air-cooled units. The price of the sealed gas-filled
units is also considerably higher than that of open air-cooled units. Because
of the poorer heat-transfer characteristics of the gas compared with liquids,
the gas-filled transformers are designed to operate at 150° C coil temperature
rise and have insulation systems limited to 220° C. Hot spots in the coils
can approach 220° C; accordingly, there is no allowance for even short-term
operation at loads higher than rated capacity. Therefore, the gas-filled
transformers must often be specified in a larger size than the liquid-filled
transformers to allow for the expected heavy load peaks of power consumption.
Cast Coil Transformers
The third class of dry transformer is the cast coil type. Cast coil
transformers have had their primary windings or both their primary windings
and their secondary windings totally encapsulated in vacuum-degassed epoxy
resin. This type of construction decreases the noise level in comparison to
other dry type transformers, and because of the thermal capacity of the encap-
sulating epoxy, the overload capacity approaches that of liquid transformers
while the fire safety advantage is about the same as that of other dry
Cast coil transformers are generally more compact, lighter, and more
shock resistant than either liquid-cooled or the other dry-type units. The
exceptional thermal performance (comparable with that of liquid transformers
in terms of running temperatures and overload capability) is achieved by
reducing resistance losses in the coil conductors. This significantly
increases manufacturing costs and initial price, but it results in decreased
electrical operating costs and is a factor in the probably longer life of
This technology is better developed in Europe than in the United States.
Although the cast coil transformers are among the most expensive in terms of
initial cost, they are gaining increased usage where reliability, small size,
and fire safety are important consideration.
Mining Machinery Transformers
Draglines, shovels, and blasthole drills that are electrically powered
use transformers to reduce the incoming high voltage to the levels used by the
drive motors. In some instances, the machinery was originally designed for
oil-filled transformers. When askarel transformers were specified by the
buyer, they were installed in the fire-resistant vaults that had been designed
for oil-filled transformers. In some cases where these customer-ordered aska-
rel units fail, they can be directly replaced with oil-cooled transformers
with little, if any, increase in fire hazard. In the event that an insurance
carrier requires fire safety in addition to an onboard vault, there is likely
to be no great difficulty in installing a silicone or high-fire-point,
In those instances where an item of mobile machinery was actually
designed with askarel transformers in mind, the installation of oil-filled
transformers might not be possible because of the lack of fire safety precau-
tions, such as fireproof vaults. Gas-cooled transformers might be adequate
replacements for askarel transformers, except that gas-cooled units are gener-
ally slightly larger in physical dimensions then comparable kva liquid-cooled
units. Silicone and high-fire-point hydrocarbon transformers might satisfy
most safety requirements at slightly higher cost than the original askarel
Several other alternatives to the use of askarel transformers on mobile
machinery were observed during the mine visits. On one dragline, there were
several oil-filled transformers, each in a steel room with appropriate vents.
Each room was equipped with a fire detection system that would set off an
alarm in the operator's cabin if a fire occurred and would also activate a
Halon 1301A fire suppression system. A second dragline, still under construc-
tion, had two large three-phase oil-filled transformers mounted on platforms
on the exterior of the machine, thereby minimizing the damage that a trans-
former fire could cause. A third possible alternative was under consideration
for a transformer on a blasthole drill. This transformer was mounted on the
rear of the machine and, in the event of a fire, could have posed a consider-
able threat to the operator. Mine personnel were planning to remove the
transformer from the drill and mount it nearby on skids so that the trans-
former posed less of a hazard but could still be moved as required. Though
this particular transformer was oil filled, this same procedure could be done
any time an askarel transformer needed to be replaced on any type of machinery
with a slight increase in electrical resistance losses.
Relative Costs of Non-PCB Replacement Transformers
The National Electrical Code allows only the smallest of oil-cooled
transformers to be used indoors without a vault. The cost of a vault can
increase the installation cost of an oil-filled transformer in place of an
askarel unit by 90 to 133 percent of the base cost of the transformer, thereby
eliminating the use of oil-filled transformers for askarel units where no
vault already exists. At voltages in excess of 35 kv, the code requires that
all types of transformers be installed in vaults if they are located in build-
ings. However, as far as the mining industry is concerned, it is unlikely
that many transformers will be installed in indoor locations handling more
than 35 kv. Therefore, the cost of vault construction will be considered here
in connection with oil-cooled transformers only.
Table 4 summarized the relative basic costs and installed costs of vari-
ous types of transformers. Askarel transformers are included for the sake
TABLE 4. - Cost comparisons of oil-filled versus other transformer
designs intended for hazardous locations, percent
(1,000 kva, 15 kv transformer)
Dry open coil air-cooled....
Dry cast coil
^atch basin is not required by law or regulation but is required as a
condition for insurance coverage by certain industrial insurers.
Sources: Westinghouse Electric Corp.
p. 18 (updated).
Is There Another Way? Sharon, Pa.
Deaken, R. F. J., and P. D. Smith (Polygon Industries Ltd.). Epoxy
Insulation — A New Generation of Dry Type Transformers. Pres. at
64th Ann. Meeting, Canadian Pulp and Paper Assoc, Montreal, Quebec,
Canada, Jan. 31, 1978.
Summary — Considerations in Choosing an Alternative to PCB Transformers
The following considerations apply to all situations in which trans-
formers are used in mining; that is, aboveground, underground, indoor, or on
Oil-Cooled Transformers : There are surprisingly large numbers of trans-
former installations, in mining and in other industries, where askarel trans-
formers have been installed in places where the prevailing electrical code as
well as common sense would have allowed the installation of oil-filled trans-
formers. If such an askarel transformer must be replaced, either because it
has failed or because in its present location it is too costly or virtually
impossible to secure against fluid loss (and therefore presents a potential
extreme cleanup threat), the first choice to be considered is an oil-filled
unit. If the use of an oil-filled transformer presents no particular fire
hazard, and if no additional fire precautions are needed such as a vault,
then the oil-filled unit will be the most cost effective and the easiest
Silicone and High-Fire-Point Transformers : Because the coolant fluids in
silicone and high-fire-point type transformers are of a higher viscosity than
either askarel or ordinary transformer mineral oil, their heat-transfer char-
acteristics are not quite as good. Thus replacement transformers of these
types are likely to be slightly larger than the askarel units they replace.
They will probably not be as heavy as the equivalent askarel units, however,
because of the extremely high density of the askarel coolant. Silicone. and
high-fire-point, hydrocarbon-cooled transformers find their best applications
as replacements for askarel transformers in places where fire vaults for oil-
filled units would either be too expensive to install or would be impractical
to install because of space limitation. Being liquid filled, they have the
advantage of having high sustained overload capacity, the same as askarel and
Dry Type Transformers : Dry, open air type transformers are usually
larger than liquid-cooled units because of the allowance that must be made for
air movement. And assuming that the unit is used in an environment where dust
is not a consideration, open air-cooled transformers can operate with less
maintenance than any of the liquid type transformers. Open air-cooled trans-
formers have two drawbacks as far as mining is concerned: They have only
short-term overload capability because they contain no liquid to act as a heat
sink, and they -tend to generate much more noise than liquid-filled trans-
formers, which can be irritating to people who have to work nearby.
Sealed gas-cooled transformers have all the same characteristics of open
transformers, except they are totally sealed against the hazards of environ-
mental dust and corrosive gases and fumes. Since they are sealed, their cases
have to be of heavy-gage construction to contain the pressure of the gas
inside when the unit is operating at high temperatures. Thus they tend to be
heavy as well as large in comparison with liquid units of equivalent rating.
Their chief advantage is their almost total freedom from maintenance, which
makes them suitable for applications where maintenance is impractical. Their
disadvantages include high initial cost, high operating noise, and poor sus-
tained overload capacity.
Cast coil transformers have advantages of both liquid and dry trans-
formers. They require virtually no maintenance, they produce noise levels
that are intermediate between liquid and other dry units, and because of
their designed-in high efficiency plus the amount of material used to encase
the windings, they can sustain high overloads almost as well as liquid-filled
transformers. Their main disadvantage is high initial cost.
About 98 percent of the liquid-filled transformers in use in the United
States (probably including the majority of those used in mining applications)
are filled with transformer oil. Analysis of oil taken from several hundred
transformers owned by electrical utilities has indicated that as many as
38 percent of all of the oil-filled transformers may be contaminated with
PCB's in concentrations exceeding 50 ppm (that is, 0.1 lb PCB ' s per ton of
oil). The contamination of transformer oil with PCB's may have occurred
either in transformer manufacturing plants where both PCB's and oil were used
to fill transformers, or in routine field servicing that involved filtering
the liquid by use of equipment that was used for both oil- and askarel-filled
units. In a few cases, PCB's may have been used to top off oil-filled
PCB's are completely soluble in transformer oil, and there is no easy way
to determine whether low levels of PCB's are present in any particular lot of
oil at concentrations above 50 ppm. The only feasible method for analyzing
for low levels of PCB's in oil involves the use of a gas chromatagraph with an
electron capture detector. A number of qualified analytical laboratories will
perform this analysis for prices ranging from $60 to $100 per sample depending
on the number of samples submitted at one time.
The EPA regulations on PCB's define "PCB-contaminated transformers" as
any oil-filled transformer in which the oil is contaminated with PCB's in con-
centrations above 50 ppm, or as any oil-filled transformer in which the oil
has not been tested and found to contain less than 50 ppm PCB's. In other
words, all oil-filled transformers must be considered to be contaminated with
PCB's unless tests must have been performed and the oil found to not contain
Transformer oil known to be contaminated with more than 500 ppm PCB's is
classified as a PCB askarel; both the oil and the transformer that it is in
are considered to be PCB askarel items and are covered by the regulations.
Transformer oil that contains 50 to 499 ppm PCB's or that has not been tested
is considered to be PCB contaminated. EPA regulations apply to the disposal
or reuse of contaminated oil, but there are no regulations on the continues
use, maintenance, rebuilding, or disposal of the transformers.
Transformer oil that is known by test to contain less than 50 ppm PCB's
is not covered by the EPA PCB regulation.
Disposal of transformer oil from PCB-contaminated transformers: By
incineration in an approved PCB incinerator; li+ by burial in an approved PCB
chemical waste landfill; by burning as an auxiliary fuel in a large power
boiler that meets specific operational requirements (see regulations for
Reuse of oil from PCB-contaminated transformers: Reclamation and reuse
of oil is allowed by the owner of the oil.
Resale of used or reclaimed oil from PCB-contaminated transformers:
Storage of out-of-service PCB-contaminated transformers or oil from such
units: Must be in a facility meeting the requirements of SPCC plan.
1H As of January 1981 EPA has not approved any incinerators for commercial
disposal of PCB's. See General Requirements, subsection on Disposal.
Spill cleanup : All material contaminated with more than 50 ppm PCB's
must be picked up and disposed of as PCB's. In general, the oil spill regula-
tions will apply and will be more stringent for low-level contamination of
land and water by oil.
Most AC power capacitors manufactured in the United States between 1935
and 1977 used PCB's as a dielectric liquid. The EPA regulations banned the
sale of PCB capacitors after July 1, 1979, unless the seller has obtained an
exemption from the regulations from the EPA. However, non-PCB capacitors have
been developed for almost all of the applications where PCB units were pre-
viously used. The liquids used to replace the PCB's in these new designs are
more flammable than PCB's, but the manufacturers have developed various
pressure-sensitive and heat-sensitive circuit breakers that prevent the capac-
itor from rupturing if it fails electrically.
The EPA regulations will allow existing capacitors to remain in service
but impose certain marking, recordkeeping, storage, disposal, and spill
4Jses of PCB Capacitors in the Mining Industry
Electronics : Small PCB capacitors were used in the power circuits of
some microwave ovens and television sets.
Motor Start Capacitors : Used in series with the secondary windings of
larger single-phase motors such as those used in room air conditioners and
submersible well pumps.
Ballast Capacitors : Used in the ballasts of fluorescent lights and high-
intensity mercury are arc and sodium arc lamps.
Power Factor Capacitors : Usually located in substations, although often
found on distribution poles.
Surge Capacitors : Used with circuit breakers in large electric motors
and on load centers.
How To Identify PCB Capacitors
Liquid dielectric type AC capacitors are sealed metal cans with two or
more terminals. The non-PCB capacitors that have been built since July 1,
1978, have all been marked "No PCB's." All other capacitors of this type must
be assumed to contain PCB's unless you know, based on manufacturer's litera-
ture or label information, that a specific capacitor does not contain PCB's.
The following is a list of the manufacturers known to have produced PCB
capacitors since 1971. PCB capacitors manufactured prior to 1971 may not
appear on this list if the manufacturer stopped using PCB's or went out of
Manufacturers Trade name of liquid
Axel Electronics NA
Capacitor Specialists NA
Cornell Dubilier Dykanol
Electrical Utilities Corp Eucarel
Electromagnetic Filter Co NA
General Electric Pyranol
Jard Corp Clorphen
McGraw Edison Elemex
P. R. Mallory and Co Aroclor B
R. F. Interonics NA
Sangamo Electric Co Diaclor
Sprague Electric Co Clorinol
Tobe Deutschmann Laboratories NA
Universal Manufacturing Corp Askarel
York Electronics ?
NA Not available.
Requirements for PCB Capacitors
PCB capacitors may continue in use indefinitely, with no special diking
provisions required. The PCB regulations define three types of PCB capaci-
tors, and different requirements apply to each type:
Types of PCB Capacitors :
Small: Contain less than 3 lb PCB's (exempted from all
requirements ) .
Large High Voltage: Contain more than 3 lb PCB's and operate at
voltages above 2,000 v (basically distribution system power
Large Low Voltage: Contain more than 3 lb PCB's and operate at
voltages below 2,000 v.
Note: In general, "large" capacitors are those having a can volume
greater than 300 cu in.
Use : No restrictions on continued use of existing PCB capacitors.
Large High Voltage: A PCB label must be applied to each capacitor
in use and in storage.
Large Low Voltage: A PCB label must be applied to each capacitor
when it is removed from service. It would probably simplify the
job of keeping track of the large PCB capacitors if the large
low-voltage capacitors in service had the label applied, but this
is not required.
Small: No marking requirements.
Recordkeeping : Required, except for those facilities having fewer than
50 large capacitors and no other PCB transformers. The records for capacitors
must include the following information: The total number of PCB large high-
voltage and low-voltage capacitors in the facility; the date each large PCB
capacitor is removed from service, is placed into storage for disposal, and is
placed into transport for disposal; for large capacitors removed from service,
the location of the initial disposal or storage facility and the name of the
owner or operator of the facility; for PCB capacitors in storage in contain-
ers, the total weight of capacitor in each container. An annual report must
be prepared summarizing this information as of July 1 of each year. All
records must be retained for 5 years after the facility ceases using or stor-
Storage for Disposal : Requirements apply to storage of large PCB capaci-
tors only. In general, capacitors must be placed in drums and stored in spe-
cial PCB storage" areas. However, nonleaking large capacitors may be stored on
pallets next to an approved storage area until January 1, 1983, provided that
(1) the storage area has immediately available unfilled storage space that
could accommodate at least 10 percent of the capacitors stored outside the
area (in case a capacitor should start to leak, it could be immediately moved
into the storage area) and (2) the capacitors on pallets are inspected
Large PCB Capacitors: In an approved PCB landfill until March 1,
1981, capacitors must be shipped in steel drums that meet DOT
requirements, and void spaces must be filled with sawdust, dirt,
or other absorbent material. The use of PCB landfills for dis-
posal of capacitors may be allowed after March 1, 1981, if no
suitable approved incinerators are available. Check with EPA
after March 1, 1981, to determine disposal requirements (toll-
Small PCB Capacitors: No special disposal requirements. May be
disposed of as any other trash.
Spill cleanup: It is uncommon, but not unknown, for a capacitor to
leak when it fails. Because of the high temperatures and pres-
sures caused by an electrical arc occurring inside a capacitor,
PCB vapors may be vented under pressure and spray over a consider-
able area. The regulations require that all material contaminated
with over 50 ppm PCB's be picked up and disposed of in an approved
PCB landfill, and that contaminated surfaces of equipment be
decontaminated. Rupture of a capacitor in an underground or
indoors application could result in high concentrations of PCB's
in the air, which would present a serious health hazard to any
workers in the area.
Precautions for Continued Use
Capacitors seldom rupture when they fail, and there is little likelihood
that a major PCB spill will result from the failure of any PCB capacitor pres-
ently in service. Even a large power factor capacitor rated at 200 kvar will
contain only about 40 lb of PCB's, and most of this is adsorbed in the paper
or other solid dielectric material. Therefore, the maximum amount that could
leak out would probably not exceed 8 lb of PCB's. In the infrequent occasion
of a rupture of a capacitor, PCB's will probably be sprayed out as a fine
mist. This will contaminate nearby objects and materials, and the contami-
nated material will have to be picked up and disposed of as PCB's.
The only significant risk that could result from continued use of PCB
capacitors would be human exposure to PCB vapors if a capacitor failed in a
building or underground installation. Most capacitors used in these environ-
ments are used as surge protection on distribution transformer primary termi-
nals and on motor contactors. In most cases, system electrical safety can be
improved by removing the capacitors and installing properly sized surge
arrestors. This system modification is discussed in more detail in the fol-
Substitutes for PCB Capacitors
PCB's are no longer being used in capacitors, and the EPA regulations ban
the sale of PCB capacitors after July 1, 1979, unless the seller has applied
for and been granted an exemption from these ban requirements. Capacitors
using non-PCB dielectric liquids are available for most applications.
Although the replacement liquids do not have the fire resistance of PCB's, the
manufacturers are improving the rupture resistance of non-PCB ballast capaci-
tors by building thermal and pressure-sensitive circuit breakers into the
capacitors. Most large high-voltage power factor capacitors are located out-
doors at substations, and there is little risk of major fire damage even if a
leak should occur and the liquid burn.
The capacitors used in buildings and in underground mines on the primary
terminals of distribution transformers and associated with motor contactors
can present a potential fire problem if non-PCB capacitors are used. These
capacitors are used to limit the rate of voltage rise and to protect the cir-
cuit breaker from flash over resulting from chopping when a motor is discon-
nected. However, recent research has shown that capacitors used in these
applications may actually degrade the electrical system performance.
The presence of too much load side capacitance can result in prestrike
when a motor contactor is closed; the capacitor should be installed on the
motor terminals rather than adjacent to the contactor as is usual practice —
the inductance of the cable will help reduce the tendency of prestrike. In
addition, the charging requirements of excess capacitance can trip out the
ground fault detector in some cases. In most cases, improved system safety
can be achieved by removing the capacitors and installing low sparkover dis-
tribution class surge arrestors that are coordinated with the insulation char-
acteristics of the associated motor and transformer. The factors that must be
considered in making this system change are discussed in detail in the follow-
Morley, L. A., and others (Pennsylvania State University). Coal Mine Elec-
trical System Evaluation. Volumes I through VII. BuMines Open File
Rept. 61-78 (set), 1977, 1,015 pp. Available for reference at BuMines
facilities in Denver, Colo., Twin Cities, Minn., Bruceton and Pittsburgh,
Pa., and Spokane, Wash.; U.S. Dept. of Energy facilities in Carbondale,
111., and Morgantown, W. Va.; National Mine Health and Safety Academy,
Beckley, W. Va.; and National Library of Natural Resources, U.S. Dept. of
the Interior, Washington, D.C.; available from National Technical Informa-
tion Service, Springfield, Va., PB 283 489/AS (set); contract G01 55003.
UNDERGROUND MINING MACHINERY
In the late 1960's and early 1970' s PCB's were used in some electric
motors manufactured by Reliance Electric for Joy Manufacturing Co. Joy used
these motors in the following applications:
CU43 continuous miners — cutting-head motors, pump motor
9CM continuous miners — cutting-head motors, pump motor
14BU10 loaders — traction motors
Liquid-filled motors were used because they were smaller and lighter than
air-cooled motors. A PCB mixture was chosen as the liquid because it was non-
flammable, provided adequate lubrication, and possessed the best overall com-
bination of electrical properties, chemical stability, and cost. The amount
of PCB's used in each of the various kinds of motors is summarized in
TABLE 5. - Quantity of PCB's in mining machinery
Weight of fluid
Weight of fluid
All of the CU43's, 9CM's, and 14BU10's originally sold by Joy used PCB-
filled motors. Some of the traction motors on the loaders have been converted
to air cooling and are no longer affected by the PCB regulation. If one of
the loaders was purchased used, and there is some doubt about whether the
motors still contain PCB's, the air-cooled motors can easily be identified
because they have no fill-plug or pressure-relief valve.
Some of the continuous miner motors have been converted to silicone cool-
ing. The shop that performed the conversion should be contacted for informa-
tion about the possibility of the motors being contaminated with small amounts
of PCB's. If the repair shop does not have any information, the following
guides should be followed;
1. If the motor was disassembled, degreased, and rewound , there is
little or no chance that any PCB's remain; thus the motor would not be covered
by EPA regulations.
2. If the motor was not rewound but was only drained, flushed, and
refilled with silicone, there were probably still enough PCB's trapped in the
motor windings to contaminate the silicone. In this case, the motor is cov-
ered by the regulations and should still be treated as though it were filled
with PCB's. The procedures and recommendations in this chapter should be
All three types of equipment may be used until January 1, 1982, under the
1. PCB's may be added to any of the motors until January 1, 1982.
2. PCB-filled motors on the loaders must be rebuilt as non-PCB motors
the next time the motor is rebuilt.
3. PCB-filled motors on the continuous miners may not be rebuilt after
January 1, 1980.
4. Any PCB's that will be used to service PCB-filled motors must be
stored in accordance with the requirements previously listed.
5. PCB motors must be disposed of in an approved chemical waste land-
fill. Disposal must take place before January 1, 1984. The regulations per-
mit used machinery to be bought and sold.
The EPA regulations require that labels be applied to anything that con-
tains PCB's. In connection with the PCB-filled motors, the following things
must be labeled immediately:
1. Each PCB-filled motor.
2. Each mining machine that still has a PCB-filled motor.
3. Each can of PCB's that is on hand for servicing or being stored for
4. Each area that is being used to store PCB's or PCB-filled motors.
The labels should be placed where they can be easily seen.
Recordkeeping : None required by the regulations.
PCB's may be added to mining machinery motors until January 1, 1982.
After this date, further use of the machinery is prohibited and any PCB's in
stock must be disposed of properly.
The motors on the continuous miners may be rebuilt until January 1, 1980.
After that date the machinery may still be used (until January 1, 1982); if a
motor fails and no spare motor is available, the machine must be retired and
the motors must be disposed of properly.
The regulations require that the motors be drained of as much liquid as
possible, and the liquid must be shipped to an incinerator that has been
approved by the EPA for disposal of PCB's. The drained motor must be disposed
of by burial in""an approved chemical waste landfill. To obtain information on
the location of approved incinerators and landfills call (toll-free,
800-424-9065, or in Washington, D.C., local 554-1404) or write the Office of
Industry Assistance, Office of Toxic Substances TS-799, U.S. Environmental
Protection Agency, 401 M St., S.W., Washington, D.C. 20460.
The motor and the liquid must be disposed of before January 1, 1984. If
the motor or the liquid will be kept for more than 30 days after the motor is
removed from service, storage must be in an area that meets the requirements
Recommended Precautions for Continued Use
The following precautions should be taken when using PCB fluids in mining
1. A pan filled with floor-dry, sawdust, or some other absorbent mate-
rial should be placed under a motor before it is topped off.
2. Drips and spills should be avoided or promptly cleaned up when top-
ping off a motor.
3. Motors should not be overfilled as this has, in some instances,
resulted in leaks.
4. Any leaking motor or any motor that is using a greater than normal
amount of fluid should be immediately removed from service until the cause of
the loss of fluid is located and eliminated.
5. If a continuous miner is going to be used much past January 1, 1980,
Joy Manufacturing Co. should be contacted as soon as possible to make arrange-
ments to have the motor rebuilt before the January 1, 1980, deadline on
Emergency Spill Response
If PCB's leak or spray out of a mining machinery motor, the procedure
described in appendix A should be followed. In addition, if the spill happens
underground the following precautions should be taken:
1. If water is being sprayed on the mine face near the machine, the
water should be shut off immediately.
2. If mine dewatering is being performed in the area of the spill, it
should, if possible, be stopped immediately. (If the dewatering system
becomes contaminated with PCB's, it will have to be thoroughly cleaned or pos-
sibly sent to a chemical waste landfill. )
Non-PCB Replacement Equipment
The traction motors on the loaders can be rebuilt as air-cooled motors.
Joy Manufacturing will do this for approximately $3,100 per motor. This is
roughly what it would cost for rebuilding the motor for continued PCB-cooled
operation. The EPA regulations do not permit the motors to be used after
January 1, 1982, and also do not permit Joy to perform the conversion to air-
cooling after January 1, 1982. For further information on having the conver-
sion performed, contact the nearest Joy sales representative or service
There is no suitable replacement for the PCB-filled motors on the contin-
uous miners. The motors cannot be rebuilt for air-cooled operation because
there is not enough room in the machinery frame. Some of these motors have
been refilled with a silicone fluid. The use of silicone fluids has not been
approved by MSHA because silicone vapors will deactivate methane detectors,
and is not recommended by Joy because the silicones will burn. Therefore,
silicone fluid cannot be considered an acceptable replacement for PCB's in
these motors. The only acceptable alternative is to purchase another miner
before the January 1, 1982, deadline.
Most separator electromagnets are filled with mineral oil, but PCB's have
been used in magnets mounted in locations where there is an increased danger
of fire. These PCB-filled magnets have been used primarily indoors near coal
crushers and over conveyors at the head of a mine, though they may be found in
There are no markings on a magnet that tell whether it is filled with
mineral oil or PCB's; PCB's were simply substituted for mineral oil at the
request of the purchaser. The simplest way to determine what a magnet is
filled with is to check company records. If records are not available, the
serial number of the magnet should be obtained from the nameplate and the
manufacturer should be contacted. Three manufacturers used PCB's in some of
4780 West Electric Ave.
Milwaukee, Wis. 53246
95 Magnet Drive
Erie, Pa. 16512
Stearns Magnetics, Inc.
6001 South General Ave.
Cudahy, Wis. 53110
PCB-filled electromagnets are considered to be totally enclosed uses of
PCB's and are subject to the same requirements as PCB transformers, except for
the recordkeeping requirement.
Any electromagnet that contains PCB's or liquid contaminated with over
50 ppm PCB's must be labeled.
Recordkeeping : None required by the regulation.
Minor servicing of PCB-filled electromagnets is permitted until July 1,
1984, but rebuilding or any other type of servicing that requires removing the
coil is prohibited. The following requirements must be followed when servic-
ing a PCB-filled electromagnet:
1. PCB's removed from the magnet must be either returned to the magnet,
used in some other permitted application, or disposed of properly. The PCB
material may not be sold.
2. Any PCB's that may be used to service or repair a PCB electromagnet
must be stored in an area that meets the requirements previously described.
The regulations require that the PCB magnet be drained of as much liquid
as possible, and the liquid must be sent to an incinerator that has been
approved by the EPA for disposal of PCB's. The drained magnet must be buried
in an approved chemical waste landfill. To obtain information on approved
incinerators and landfills, call (toll-free, 800-424-9065, or in Washington,
D.C., local 554-1404) or write the Office of Industry Assistance, Office of
Toxic Substances TS-799, U.S. Environmental Protection Agency, 401 M St.,
S.W., Washington, D.C. 20460.
Before the liquid is drained from the magnet, the ground or floor under-
neath should be covered with a sheet of plastic and a layer of floor-dry, saw-
dust, or other absorbent material. If the magnet does not have a drain plug,
a hole should be drilled or cut in one corner of the top of the magnet and the
fluid should be siphoned into a barrel or drum that meets the requirements
described above and that is acceptable to the incineration facility that will
be receiving the fluid. Some incinerator operators may require that small
drums of liquid be packed inside of larger barrels of sawdust to provide more
protection against spills, so the incinerator facility should be contacted to
determine its requirements. After the magnet has been thoroughly drained, the
siphoning hose should be placed inside the magnet case and the hole should be
plugged to prevent any small amounts of PCB's that remain in the magnet from
leaking out when the magnet is sent to the landfill. If any PCB's dripped
onto the layer of floor-dry, the contaminated material and, if necessary, the
plastic must also be sent to the landfill.
For additional information on transportation of PCB's see General
Recommended Precautions for Continued Use
Precautions should be taken to reduce the possibility of spills and leaks
when using a PCB-filled electromagnet. These steps include:
1. Inspecting the magnet at least once a month for minor leaks, with
particular attention being paid to the welds, where cracks may develop if the
magnet is frequently turned on and off.
2. If the magnet is being moved, extra care should be taken to insure
that the casing is not damaged.
The EPA regulations allow continued use of PCB-filled separator magnets
over coal conveyors because it is assumed that any PCB's that leak out of the
magnet will be destroyed when the coal is burned. However, the use of PCB
magnets over coal that will be washed or otherwise subjected to water-based
physical cleaning processes risks a major PCB contamination incident. Washing
coal that has been contaminated with spilled PCB's will result in PCB contami-
nation of the wash water, exposure of workers to PCB's vaporized from the
recycled water, and stream pollution when the water is discharged from the
plant. A major spill of PCB's into the water of a coal cleaning plant,
whether directly or due to contamination of the feed coal, would have to be
considered an environmental disaster that would be extremely expensive, if not
impossible, to clean up. The consequences of a possible PCB spill should be
carefully considered when deciding whether to allow a PCB separator to remain
Emergency Spill Response
If a PCB-filled magnet develops a leak, the spill response plan in appen-
dix A should be followed. In addition, the following steps should be taken:
1. The conveyor should be stopped immediately to limit the amount of
coal that becomes contaminated.
2. The magnet should be removed from over the conveyor, and a pan of
sawdust or floor-dry should be placed on the conveyor under the leak.
3. Any visibly contaminated coal should be removed from the conveyor and
placed in a drum for disposal.
4. See General Requirements for decontamination procedures.
Several alternatives to the use of PCB-filled electromagnets are availa-
ble. Oil-filled magnets can be used if there is a location where the
increased fire risk would not pose a significant threat.
The magnet manufacturers also sell silicone-filled magnets for use where
a fluid with fire-resistant properties is required. A silicone-filled elec-
tromagnet costs 40 to 50 percent more than a comparable oil-filled unit. The
use of silicone fluids underground is not recommended because silicone vapors
will deactivate methane detectors. Although the silicone fluid is nontoxic,
major spills onto coal (or ore) prior to wet flotation processing may disrupt
the process because silicone is a powerful antifoaming agent.
Other high-fire-point hydrocarbon transformer liquids might also be con-
sidered. These have about the same fire-point characteristics as silicone,
but they release more heat than silicone if they do ignite.
Repeated refilling of existing PCB separator magnets with transformer
oil, silicone, or high-fire-point transformer liquid will gradually reduce the
residual levels of PCB's. If the concentration of PCB's is reduced to below
50 ppm, the magnet would be allowed to be rebuilt or sold for scrap when it
fails. (The regulations allow these alternatives for transformers containing
less than 500 ppm PCB's. Rebuilding or scrapping a magnet having PCB's pres-
ent in the fluid in concentrations between 50 and 500 ppm would require the
owner to apply to the EPA for an exemption based on the precedent established
Dry-type separator magnets are also available. Eriez sells an air-cooled
magnet that has been approved by Underwriters Laboratory for use in dirty,
dusty environments. This type of magnet costs 20 to 25 percent more than a
comparable oil-filled unit.
HEAT -TRANSFER FLUIDS
Because of their fire resistance and stability, PCB's were used as the
major component of several high-temperature heat-transfer fluids. These
fluids were manufactured from 1930 through 1972 by Monsanto. From 1972
through 1974 Geneva Industries of Houston, Tex., manufactured one type of
PCB-based heat-transfer fluid. Monsanto quit selling PCB-based heat-transfer
fluids during 1971-72, but it was several years before all the fluid was in
the hands of the final consumer. Most purchasers of heat-transfer fluids were
advised by Monsanto to drain their systems and refill them with a different
fluid. Recent tests on a number of heat-transfer systems have found PCB's
present at levels high enough to be regulated by the EPA even in systems that
have been drained and flushed.
PCB-based heat-transfer fluids manufactured by Monsanto are shown as
Use : Heat-transfer systems containing fluid contaminated with more than
50 ppm PCB's may be used until July 1, 1984, provided that:
1. Every heat-transfer system that ever contained PCB-based fluid had to
be tested by October 1, 1979, to determine the concentration of PCB's
remaining in the fluid.
2. If the concentration of PCB's exceeds 50 ppm:
(a) The system must be drained and refilled with fluid free of
PCB's within 6 months. The PCB-contaminated fluid must be
properly stored and disposed of in an approved PCB incinerator.
(b) The testing and refilling procedure must be repeated annually
until the concentration of PCB's is found to be less than
50 ppm at least 3 months after the most recent replacement of
(c) Records of the testing and refilling must be maintained for at
least 5 years after the concentration of PCB's is reduced to
Any heat-transfer system that contains a fluid with over 50 ppm of PCB's
must be marked immediately. The label should be placed where it can be easily
seen. Names and addresses of label printers are listed under General
All records resulting from any test conducted to determine the PCB con-
tent of the fluid in a heat-transfer system must be kept for at least 5 years
after the system is determined to have a concentration of PCB's in the fluid
of less than 50 ppm.
Any type of servicing may be done on contaminated heat-transfer systems.
The only restriction is that fluid containing 50 ppm or more of PCB's may not
be used to refill or top off a system. This includes fluid that has been
removed from a system during servicing.
Fluid containing over 50 ppm of PCB's may be processed in some manner to
reduce the level below 50 ppm, and then the fluid may be used in a heat-
transfer system. This processing may be done by the owner of the system or by
someone who has received authorization from the EPA to perform this type of
Any fluid removed from a system that contains any level of PCB's must
either be processed or disposed of in an approved incinerator. Some land-
fills may accept liquids with less than 50 ppm PCB's for disposal. Fluid
contaminated with any detectable amounts of PCB's may not be used for road
oiling, as an herbicide carrier, or in any other similar application.
When a PCB-contaminated (above 50 ppm PCB's in the fluid) heat-transfer
system is taken out of service and will no longer be used, the fluid and the
system must be disposed of separately. The fluid must be sent to an approved
PCB incinerator. The drained heat-transfer system must then be disposed of by
burial in an approved chemical waste landfill.
Once the system is drained, it must be carefully disassembled for ship-
ment (unless it is possible to ship the system whole). Plastic and floor-dry
should be placed under each joint before it is taken apart. The landfill and
the shipping company should be contacted for instructions on packaging por-
tions of the system that are too large to fit in 55- or 110-gal drums. All
containers that hold contaminated liquids and parts of the system must be
labeled. If any of the material is going to be stored for more than 30 days
before it is shipped to the disposal site, it must be stored in an area that
meets the requirements described in General Requirements.
Disposal of scrapped PCB heat-transfer systems in a chemical waste land-
fill will be expensive. Present costs are about $8 per cu ft plus transporta-
tion, and the owner of the machine also loses the scrap value of the metal.
It may be cheaper to decontaminate the system using a solvent such as fuel
oil, even though the contaminated solvent would require disposal in an
Recommended Precautions for Continued Use
The following precautions are recommended when using a heat-transfer sys-
tem that is contaminated with PCB's:
1. If a major leak in the system could reach the ground or any water
drain, the system should be diked.
2. Any drains or cracks in the floor near the system should be plugged
3. If there are minor leaks in the system and it is impractical or
impossible to repair them, a pan of floor-dry or sawdust should be used to
catch the leakage. The pans should be emptied periodically. Contaminated
floor-dry and sawdust should be accumulated in a drum. This drum must be
marked, stored in an area that meets the requirements previously described,
and disposed of in an approved chemical waste landfill.
4. The system should be checked at least once a month for leaks.
5. When servicing is necessary, pans of floor-dry or a layer of plastic
and then a layer of floor-dry should be placed under all joints that will be
disassembled or that could leak as a result of being stressed while working on
a different part of the system.
6. When a pump, piping, or other component of a system is removed, the
ends or other openings should be plugged with rags, or the other component
should be supported on a rack, pallet, wooden slats, or in some other manner
such that plastic or pans and floor-dry can be placed under all openings that
may leak PCBs.
Emergency Spill Response
In the event of a leak from a heat-transfer system, the spill response
plan in appendix A should be followed. In addition, the following steps
should be taken:
1. The heat should be shut off.
2. Any pumps in the system should be shut off.
3. If the leak is in a high-pressure portion of the system, the pressure
should be relieved as rapidly as possible.
4. The system should be drained below the level of the leak as rapidly
Non-PCB Heat-Transfer Fluids
When Monsanto discontinued the sale of PCB-based heat-transfer fluids in
1972, it made available a number of substitute fluids for high-temperature,
low-pressure heat-transfer systems. Suitable fluids are also available from a
number of other manufacturers. These fluids are mostly of the chemical type
of alkylated aromatics and aromatic ethers.
The non-PCB fluids have two disadvantages compared with the PCB-based
materials: (1) The non-PCB fluids are flammable, and (2) they will oxidize
upon prolonged exposure to air at high temperatures. As a result, conversion
to non-PCB fluids requires that the expansion reservoir be sealed and blan-
keted with an inert gas such as nitrogen to protect the fluid from oxidation.
Direct-fired systems must be protected against a major fire resulting from a
break in the fired tubes by installing a remotely controlled steam, Halon, or
carbon dioxide quench system in the combustion chamber. Information required
to design specific applications is available from insurance underwriters and
from the National Fire Protection Association, 470 Atlantic Avenue, Boston,
Mass. 02210, telephone 617-482-8755.
PCB's were used as the basis of a number of fire-resistant hydraulic flu-
ids sold prior to 1972. These fluids were used primarily in die casting
machines and in various hot metal equipment in steel mills. This study did
not identify any use of PCB-based hydraulic fluid in mining machinery or in
mine-related operations. However, it is possible that PCB-based fluid may
have been used to some extent in the raining industry, and the EPA regulations
apply to all systems that ever used PCB-based fluid, including mine
The only known supplier of PCB-based hydraulic fluid was Monsanto, which
marketed a number of different types prior to 1972, under the following trade
names: Pydraul A-200, Pydraul AC, Pydraul AC-28, Pydraul F-9, Pydraul 135,
Pydraul 150, Pydraul 230, Pydraul 280, Pydraul 312, Pydraul 540,
Pydraul 540-A, and Pydraul 625.
Any system that ever contained a PCB-base hydraulic fluid must be tested
by October 1, 1979, to determine the concentration of PCB's remaining in the
system. Requirements for recordkeeping, marking, flushing, and periodic test-
ing of contaminated hydraulic systems are the same as for contaminated heat-
transfer systems. Disposal of drained hydraulic sytems is not regulated if
the liquid contains less than 1,000 ppm PCB ' s ; flushing prior to disposal is
required if the fluid contains over 1,000 ppm PCB's. Disposal of fluid con-
taminated with over 50 ppm PCB's must be in an approved PCB incinerator.
Non-PCB Hydraulic Fluids
Most systems that used PCB-based fluids have been converted to fluids
based on phosphate esters or to water-glycol mixtures. Performance has been
satisfactory, although neither of these substitute materials has the fire
resistance or oxidation resistance of PCB's.
Analysis of phosphate-ester-based hydraulic fluids for residual PCB's
will cost more than will similar tests on hydrocarbon-based fluids because the
phosphate interferes with the equipment that is usually used to perform this
analysis. There should be no special problems if you tell the analytical lab
what type fluid is presently in the system.
Over 1 billion gal of used oil per year is collected for use as road oil
or is reclaimed for use as lubricating oil. The used oil that is re-refined
for use as lubricating oil often contains industrial oil such as used trans-
former oil and hydraulic fluid that is contaminated with low levels of PCB's.
As a result, much of the re-refined motor oil contains low levels of PCB's,
and dissipative uses of even segregated motor oil can release PCB's into the
The use of waste oil containing any detectible levels of PCB's as road
oil, insecticide carrier, or other dissipative use is forbidden. The regula-
tions do not define the analytical method to be used to check for PCB's, but
the commonly used gas chromatagraph can easily detect PCB's at concentrations
of 1 or 2 ppm in used oil.
The major impact of this ban on the use of PCB-contaminated waste oil
will be on the oiling of mining roads. Alternatives to discontinuing road
oiling included the use of carefully segregated used virgin motor oil, testing
each batch of oil for the presence of PCB's (at a cost of $50 to $70 per
batch), the use of synthetic soil stabilization chemicals, or the use of water
for dust control. A synthetic material that may perform satisfactorily is
Coherex, manufactured by Witco Chemical Corp. The manufacturer should be con-
tacted for additional information and recommendations.
Proper disposal of used oil will be required to prevent the release of
low levels of PCB's into the environment. Used oil may be used as a fuel or
re-refined without special handling provided that the oil contains less than
50 ppm PCB's.
APPENDIX A. --OUTLINE OF PCB SPILL RESPONSE GUIDE
EMERGENCY SPILL RESPONSE GUIDE FOR POLYCHLORINATED BIPHENYLS
(PCB's, Askarel, Pyranol, Inerteen, etc.)
What are PCB's: PCB's are a nonflammable oil used as a coolant and electrical
insulating fluid in some transformers, capacitors, and sepa-
rator magnets and in electric motors on certain Joy continu-
ous miners and loaders.
Hazards: PCB's are a toxic environmental pollutant. Do not breathe
vapors or get on skin. Do not allow spilled PCB's to get
into drains, sewers, or other water.
First Aid: Skin contact: Wash off with waterless hand cleaner using
paper towers. Store contaminated towels for special dis-
posal. Eye exposure: Flush with water. Vapor exposure:
Get medical aid.
Spill from live electrical equipment: Disconnect power, call chief
electrician (telephone )
Then try to plug leaks with rags, stick, or other material.
Call (environmental engineer, mine superintendent, etc.) (telephone )
Protective Use plastic gloves to prevent contact with skin. Contami-
clothing: nated gloves, clothing, shoes, etc., should be put into 55-
gal drum for disposal as PCB's. Tools may be decontaminated
by washing with solvent; dispose of solvent, rags, etc., as
Control spill: Dike major spills with dirt or other material. Soak up
spilled PCB's with rags, straw, or other material. Do not
let PCB's run into drains or water.
Final cleaning: Check with (mine environmental engineer), at (telephone )
for detailed instructions.
Disposal of PCB- Solids — load into 55-gal drums; label with PCB label; ship to
Contaminated EPA-approved PCB chemical waste landfill. Liquids — drain
Material and into 55-gal drums; flush equipment with solvent such as kero-
Equipment: sene or fuel oil to remove as much residual PCB as possible;
drain solvent into drums; apply PCB label and store in secure
roofed area meeting EPA requirements until an approved incin-
eration facility becomes available for the disposal of PCB's.
Copper plumbing pipe with cap and fitting.
APPENDIX B.— WATER-ONLY DRAINAGE SYSTEM 1
The drainage system
described below is designed
so that water can freely
flow out of the diked area,
while askarel (PCB) fluid
that is denser than water
will cause a silicone rubber
"flapper valve" to float up
into a position covering the
drain hole. Figure 6 shows
the complete water-only drainage system in side and top views, but without the
filter screen system that covers the valve and keeps leaves and other particu-
late matter from clogging the valve.
The fabrication and installation sequences of the valve are as follows:
1. Cut a 4-inch-long, straight, undented section of 1/2-inch (ID) copper
2. Place a copper cap on one end and a copper fitting having a 1/2-inch
male pipe thread on the other end and then braze (do not solder) the three
pieces together to thoroughly seal the joints (fig. B-l). Brazing is neces-
sary to allow for the additional high-temperature brazing processes that are
necessary for adequate strength of the finished valve.
3. From a piece of 1/8-inch-thick copper flat stock, cut a strip that is
2-5/8 inches long and 5/8 inch wide. This will be the "valve face." Braze it
onto the part above in this manner (as shown in fig. B-2) .
FILL WITH BRONZE FOR
^ENTIRE LENGTH, BOTH SIDES
FIGURE B-2. - Valve face.
i This appendix is reprinted with permission from the Naval Facilities Engi-
neering Command and Versar, Inc. Any questions regarding the information
in this appendix should be referred to Versar, Inc., 6621 Electronic Drive,
Springfield, Va., 22151. It originally appeared in the following report:
Versar, Inc. Guide for the Management of Askarel Transformers. Rept. to
Naval Facilities Engineering Command, Alexandria, Va., March 1979, pp. 41-
49; contract NOOO-25-78-C-0020.
4. Drill a 3/16-inch hole as shown and then cut away excess metal around
the hold and gently grind the entire surface of the valve face on fine emery
paper backed by a flat surface to remove any unevenness of the face
5. From 1/8-inch-thick copper flat stock, cut two pieces measuring
3/8 inch by 5/8 inch and braze them onto the valve face in the position shown
in figure B-4.
6. From 1/8-inch, flat copper stock, cut a rectangular piece measuring
2 inches by 6-3/8 inches. Bend it to the shape shown in figure B-5 to make
the "guard plate."
BOTTOM VIEW OF VALVE FACE
FIGURE B-3. - Bottom view of valve face.
FIGURE B-4. - Two pieces brazed on valve face.
2" 2 1/4"
GRIND OFF EXCESS METAL AT
THE ENDS, TO THE DIMENSIONS
FIGURE B-5. - Rectangular piece of copper for "guard plate."
7. Braze the "guard plate" to the main body of the valve as shown in
8. From 1/8-inch flat copper stock, cut a rectangular piece — the "valve
rest" — measuring 5/8 inch by 3-3/8 inches, and braze it onto the valve in this
position (see note 1 in fig'. B-7) .
DRILL AND TAPE 1/4-20(2)
DRILL AND TAP
FIGURE B-6. - Brazing of "guard plate" to main body of valve.
(NOTE #2: THE REASON THE "VALVE REST" SHOULD
BE ROUGHENED IS TO LESSEN THE
CHANCES THAT THE SILICONE "FLAPPER
VALVE" WILL STICK TO THIS SURFACE,
BECAUSE THEN THE FLAPPER WILL NOT
FLOAT PROPERLY IF IT SHOULD EVER
COME TO BE SURROUNDED WITH PCBs
FROM THE TRANSFORMER.)
(NOTE #1: USE A COARSE WIRE
BRUSH TO ROUGHEN THE
UPPER SURFACE OF THE VALVE
REST BEFORE BRAZING INTO
VALVE FACE —
0.1900" +- 0.025"
VALVE REST — *
+ 3/16"-+ 1/16"
t — i
FIGURE B-8. - Bearing support holes and hole-locating jig.
9. Drill a 1/8-inch hole through each of the two (bearing supports) in
the location shown in figure B-8. (It might be useful to make an alineraent
jig to facilitate the finding of the center for this hole; a schematic of the
type of jig that might be useful is shown. )
10. After all the brazing processes are finished, the copper will have a
coating copper oxide scale. Remove the scale with a rotary wire brush, but be
careful not to mar the smooth valve face. Use fine emery paper and light fin-
ger pressure to remove scale from the valve face. If there are large irregu-
larities on the valve face, remove them with a fine flat file or use fine
emery paper backed with a solid flat surface.
The flapper valve must have these dimensions (see fig. B-9) .
There are several ways to make these
'flapper valves," the two easiest
(a) On a smooth flat surface, pour out a 5/8-inch-wide, or wider,
strip of the uncured silicone rubber; make it at least 5/16 inch
thick. Locate the Teflon tube so that it is perpendicular to
the strip and 5/32 inch (±0.020 inch) off the flat surface.
When the rubber has cured, use a razor blade to cut the flapper
valve into the required dimensions. The critical dimensions and
characteristics are —
#14 TEFLON TUBE
(WALL THICKNESS = 0.016"
ID = 0.064" TO 0.074")
FIGURE B-9. - Silicone rubber for "flapper valve."
k-5/32" -+ 1/32"
FIGURE B-10. - "Flapper valve" as made by method (a).
(1) One surface of the flapper must be very smooth in order to
seal the drain hole tightly when PCB's are present in the
(2) The location of the Teflon tube must be accurate in both
alinement with the rest of the flapper and at height from the
faces of the flapper.
If these two conditions are not met, the flapper may bind
during operation when it is supposed to float in PCB's and/or
it may not properly cover the drain hole (see fig. B-10).
(b) The second method is to make a metal or plastic pattern of the
flapper valve. The pattern can be used to make a reusable mold
out of plastic or metal. Since the flapper valve is symmetric,
the two mold halves can be identical in shape. (However, one of
the mold halves should have a roughened face so that one side of
the flapper valve will also be rough; the roughness will be on
the side of the flapper valve that is away from the drain hole,
and the purpose of the roughness is to minimize sticking of the
flapper valve to the "valve rest" during the period of years
that it may lie in the open position. )
Each mold half should look like that shown in figure B-ll.
Use parting compound on the mold halves and do so sparingly on
the face that is to be smooth.
A LENGTH OF #14 TEFLON TUBE
CAN BE LAID ACROSS THIS TROUGH
BEFORE THE MOLD HALVES ARE
CLOSED; IN ORDER TO MAKE SURE
THE TUBE REMAINS STRAIGHT, CAST
THE SILICONE RUBBER AROUND IT
WHILE THE 1/16-INCH BRASS HINGE
SCREW IS INSIDE THE TUBE.
FIGURE B-ll. - Mold half for pattern of "flapper valve."
After casting, cut away the excess rubber (the flash) and (after
removing the brass hinge screw) cut the Teflon tube to the
proper length — that is, approximately 1/32 inch or 0.030 inch
excess tubing on each side of the flapper valve.
12. The flapper is attached to the valve body by means of a brass hinge
screw and four Teflon washers measuring 0.020 inch in thickness and with an
inside diameter of 1/16 inch and an outside diameter of 1/4 to 3/8 inch. The
hinge screw must have the dimensions shown in the diagram below, and the Tef-
lon washers must be placed as shown. The nut should be run down tight against
the end of the threaded portion of the hinge screw to provide adequate tight-
ness of the nut and screw. The final assembly should allow the flapper valve
lots of free play (fig. B-12).
13. The filter screen is not to be attached until after the entire valve
assembly is in place in the dike. Installation of the valve assembly on the
dike should follow this sequence:
(a) A 1/2-inch galvanized pipe flange should be cut in the manner
shown in figure B-13 so that it can be fitted low on the inside
of the steel dike.
(b) The drain valve is screwed into the flange tightly, and then the
combination of flange and valve is fitted and put into position
on the inside of the dike, as shown in figure B-14.
TEFLON WASHER (4)
1/16" D BRASS
FIGURE B-12. - Hinge support for flapper valve.
FIGURE B-13. - Pipe flange.
IF THERE IS INTEFERENCE AT
THIS POINT, DO NOT BEND THE
VALVE REST; EITHER MAKE THE
VALVE LONGER, OR GRIND
METAL OF THE DIKE.
~ FLANGE MUST BE
> FLUSH WITH DIKE
GUARD PLATE SHOULD /*
REST ON MOUNTING PAD
FIGURE B-14. - Fitting of drain valve and flange into inside of dike.
(c) Remove the flange from the valve and then, after the bolt holes
are drilled in the dike, locate and drill the center drain hole
in the dike, using the flange to locate the position of the
center hole. (Drill a hole of about 3/4-inch diameter, or at
least drill a smaller hole that will be positioned so as to
allow all water to drain from the valve.)
(d) Screw the valve back into the flange tightly and, sealing the
face of the flange with silicone rubber caulking compound or
some other weatherproof sealant, screw the flange and valve
assembly tightly into place on the dike.
(e) Additional sealant on the tops of the flange screws and around
the edge of the flange will help assure a liquid-tight seal.
CRIMP THE SCREEN DOWN
TIGHTLY ALONG ALL SURFACES
OF THE DIKE AND MOUNTING
FIGURE B- 1 5. - Screen covering valve system.
(f) Using brass or stainless steel screen with holes not larger than
1/16 inch on an edge, fabricate the filter screen so that it is
bolted into place by the screws that mount into the "guard-
plate," and so that it completely covers the valve system all
the way down to the concrete and to the bottom and side of the
dike. The arrangement for the screen should appear something on
the order of that shown in figure B-15.
The hold-down screws should be 1/4-20, hex-head copper, brass,
or stainless steel. Washers of the same material should be used
under the screws and on top of the screen in order to keep the
screen from binding and wrapping up on the screws when they are
tightened. Bolt holes can be made in the screen by either a
punch or by piercing with an ice pick-like tool having a shank
diameter of about 1/2 inch or slightly larger. It is imperative
that all sides of the valve system be protected by the screen,
because the movement of leaves and other particulate matter into
the valve area can keep the valve from functioning properly.
<?U.S GOVERNMENT PRINTING OFFICE: 1981-703-002/25
INT.-BU.OF MINES,PGH.,PA. 25251
. . . _ . /\ l ™ : y% : -SR-v ? v *°™ : . ^ "
V .^'sLf* V
o. »• ,G V "'o *^T* A
.1* * ,
4 o >. oy* 5 ^
5> vl^L'* *>
<* Safe; ^ c *^' *°° <*
f " V'*
^ >*\ii»i,\. /.^:-A ^,-^X /,^:X'-.y
DOBBSBROS. ,0^ \3 *7*^ i f>* A
^.^ .V^SPT- ^v*' - '^.^ v« ^^'